MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Scripta Materialia' source. Thu, 18 Mar 2010 16:59:40 +0100 http://www.medworm.com/index.php?rid=3358815&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210001399%2Fabstract%3Frss%3Dyes (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358815 Fri, 12 Mar 2010 16:56:35 +0100 3358815 http://www.medworm.com/index.php?rid=3358839&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000783%2Fabstract%3Frss%3Dyes The authors apologize for the error in reference 12 on page 4. The correct reference is listed below: [12] O. Engler, in: Proc. of REX’96, 1997, p. 503. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358839 Tue, 02 Mar 2010 00:00:00 +0100 3358839 http://www.medworm.com/index.php?rid=3311546&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210001120%2Fabstract%3Frss%3Dyes (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311546 Fri, 26 Feb 2010 17:05:14 +0100 3311546 http://www.medworm.com/index.php?rid=3294480&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000904%2Fabstract%3Frss%3Dyes (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294480 Mon, 22 Feb 2010 17:19:21 +0100 3294480 http://www.medworm.com/index.php?rid=3311571&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000308%2Fabstract%3Frss%3Dyes The author regrets that the captions for Figs. 3 and 4 on page 3 are incorrect. Please find the correct captions listed below: Fig. 3. (a) Microstructure of upper bainite (b) in which the carbide M7C3 precipitates with zone axis after impact at a strain rate of 1×103s−1. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311571 Tue, 16 Feb 2010 00:00:00 +0100 3311571 http://www.medworm.com/index.php?rid=3358827&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS135964621000076X%2Fabstract%3Frss%3Dyes Sub-microcrystalline nickel produced by pulsed electrodeposition was investigated during cyclic deformation at high plastic strain amplitude. After a certain number of loading cycles the specimen developed a “macro” shear band at 45° with respect to the tensile axis, which acted as a crack initiator. Electron backscatter diffraction revealed that the shear band consists of relaxed grains elongated along the shear plane, showing a typical shear texture. The shear band texture was reproduced with the viscoplastic self-consistent polycrystal model using {111}〈110〉 slip systems. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358827 Wed, 10 Feb 2010 00:00:00 +0100 3358827 http://www.medworm.com/index.php?rid=3358825&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000746%2Fabstract%3Frss%3Dyes CoPt films without and with underlayers of Pt, Ru, Ag or Au were deposited on MgO(111) substrates by magnetron sputtering at 350°C. Using a Pt underlayer resulted in an epitaxially grown Ll1 structure with enhanced chemical ordering, a high perpendicular anisotropy energy of 2.1×106Jm–3, and an anisotropy field of 2.4MAm−1 at 4K, which reduces the Ll1 ordering temperature to under 200°C and produces a room-temperature anisotropy field that exceeds 1.6MAm−1, indicating potential application for magnetic recording. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358825 Wed, 10 Feb 2010 00:00:00 +0100 3358825 http://www.medworm.com/index.php?rid=3358821&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000795%2Fabstract%3Frss%3Dyes White beam Laue micro-diffraction was performed on directionally solidified, single-crystal Mo pillars in the as-grown state, after focused ion beam (FIB) milling and after pre-straining. The Laue diffraction peaks from the as-grown pillars are very sharp and show no broadening, similar to those from single-crystal Si wafers. Significant broadening and streaking of the peaks occurred after FIB milling and pre-straining, indicative of the damage these treatments induce in the nearly perfect crystal structure of the directionally solidified Mo pillars. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358821 Wed, 10 Feb 2010 00:00:00 +0100 3358821 http://www.medworm.com/index.php?rid=3358816&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000734%2Fabstract%3Frss%3Dyes Through an extensive atomic-scale investigation of , a cementite-like structure, we show that only a proper account of saddle-point pressures leads to unambiguous jump attempt frequency spectra. We also demonstrate that attempt frequencies can spread over ranges exceeding five orders of magnitude and therefore cannot be realistically described by simplified few-valued schemes, as commonly assumed. These issues cast doubt on generally admitted assumptions in kinetic simulations, which may have critical consequences on their accuracy. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358816 Wed, 10 Feb 2010 00:00:00 +0100 3358816 http://www.medworm.com/index.php?rid=3358835&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000680%2Fabstract%3Frss%3Dyes The influence of the spark plasma sintering (SPS) heating rate on densification, microstructure and strength of ZrB2–20vol.% SiC composites with or without 5vol.% Yb2O3 addition was assessed. A low heating rate promoted densification, induced grain growth and slightly increased the strength in the Yb2O3-free ceramics, whereas the low heating rate inhibited the densification, maintained the grain size and greatly decreased the strength in the Yb2O3-doped composites. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358835 Mon, 08 Feb 2010 00:00:00 +0100 3358835 http://www.medworm.com/index.php?rid=3358828&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000722%2Fabstract%3Frss%3Dyes Synchrotron X-ray diffraction analysis of three-dimensional residual stress fields in laser-pulsed uncoated and CrN-coated steels was performed by a combination of two complementary synchrotron approaches. In the uncoated steel, the measurements revealed crater-like tensile stress distributions close to thermal cracks. For the coated samples, a regular Gaussian distribution was observed for steel whereby a cracking occurs in CrN as a consequence of steel buckling. The data also revealed the mechanism by which hard coatings protect steel from thermal fatigue. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358828 Mon, 08 Feb 2010 00:00:00 +0100 3358828 http://www.medworm.com/index.php?rid=3358818&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000709%2Fabstract%3Frss%3Dyes Double oxide phases combining a transition metal and a noble metal have recently become a subject of investigation as solid lubricant materials for high-temperature tribological applications. Here, we study the changes in chemistry and crystal structure of silver molybdate (Ag2Mo2O7) and silver tungstate (Ag2WO4) thin films and powders from 25 to 600°C. We show, using ab initio molecular dynamics, high-temperature X-ray diffraction, high-temperature Raman spectroscopy and differential scanning calorimetry in combination with sliding tests, that the layered atomic structure of silver molybdate facilitates sliding, resulting in a low coefficient of friction ( (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358818 Mon, 08 Feb 2010 00:00:00 +0100 3358818 http://www.medworm.com/index.php?rid=3358838&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000643%2Fabstract%3Frss%3Dyes Three different glasses in the system Na2O/K2O/Al2O3/KF/BaF2/SiO2 were crystallized. After cooling, in one sample only cubic BaF2 was detected, in the second sample predominantly the orthorhombic modification was found, and in the third sample, both phases were present. The orthorhombic phase according to the literature is thermodynamically stable only at high pressures. During crystallization, compressive stresses cannot relax and the orthorhombic phase is formed. This is the first experimental evidence of the formation of high pressure during crystallization of glass. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358838 Thu, 04 Feb 2010 00:00:00 +0100 3358838 http://www.medworm.com/index.php?rid=3358837&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000655%2Fabstract%3Frss%3Dyes We have developed a low-temperature and normal-pressure method for the growth of oriented rutile TiO2 nanorod arrays on transparent conductive F-doped tin oxide (FTO) substrate. Owing to the direct electronic pathway, these rutile TiO2 nanorod array films show more efficient charge-collecting ability than rutile nanoparticle films when used as photoanodes for dye-sensitized solar cells. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358837 Thu, 04 Feb 2010 00:00:00 +0100 3358837 http://www.medworm.com/index.php?rid=3358836&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000667%2Fabstract%3Frss%3Dyes Third-order nonlinear optical susceptibilities (χ(3)) of thallium–tellurite (Tl2O–TeO2) glasses doped separately with various metal oxides (MOY/X; M=22Ti(IV), 30Zn(II), 31Ga(III), 82Pb(II) and 83Bi(III)) were investigated using a femtosecond Z-scan technique. Surprisingly, the highest change in refractive index was obtained for M=Ti other than Pb and Bi, which was attributed to the formation of the TeO2/TiO2 glass structure without destruction of the initial three-dimensional network, accounting for a strong dielectric response intrinsic to pure TeO2 glass. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358836 Thu, 04 Feb 2010 00:00:00 +0100 3358836 http://www.medworm.com/index.php?rid=3358831&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000679%2Fabstract%3Frss%3Dyes In this paper, fatigue crack initiation and the propagation stages of a TiNi shape memory alloy are examined using a low cycle fatigue interrupted test. Submitted to fatigue cyclic loading, the response of the alloy presents a classical pseudoelastic response. Two potential initiation crack areas are highlighted: at the phase interfaces and at the grain boundaries. Propagation results from the coalescence of many microscopic cracks. These two stages are detectable in the last 20% of the total fatigue life. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358831 Thu, 04 Feb 2010 00:00:00 +0100 3358831 http://www.medworm.com/index.php?rid=3358830&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000618%2Fabstract%3Frss%3Dyes Sulphur segregation to grain boundaries, surfaces or interfaces seriously degrades the performance of many metallic systems. The addition of appropriate dopants may reduce the sulphur effect. Here we present a first-principles study to provide physical insights into Hf and Pt interactions with S in Ni. The pair affinities are assessed through total energetics, electron localization function and differential charge density analyses. Calculations show that Hf can effectively getter S and hence inhibit S segregation even at high temperatures, while Pt cannot. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358830 Wed, 03 Feb 2010 00:00:00 +0100 3358830 http://www.medworm.com/index.php?rid=3358829&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000631%2Fabstract%3Frss%3Dyes Fully reversed strain-controlled tension–compression fatigue experiments were conducted on extruded Mg6Al1ZnA (AZ61A) magnesium alloy by employing thin-walled tubular specimens in ambient air. The strain–life fatigue curve displayed a detectable transition from lower cycle fatigue region to higher cycle fatigue region in the vicinity corresponding to a strain amplitude of 0.5%. When the strain amplitude was higher than 0.5%, shear cracking and significant twinning were observed. When the strain amplitude was lower than 0.5%, tensile cracking and little twinning were observed. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358829 Wed, 03 Feb 2010 00:00:00 +0100 3358829 http://www.medworm.com/index.php?rid=3358832&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000552%2Fabstract%3Frss%3Dyes Cyclic softening is observed in the polycrystalline Ni-based superalloy R104 at elevated temperatures. Using transmission electron microscopy characterization methods, the damage evolution in fatigued specimens was studied. The observed deformation modes include paired APB shearing, intense planar dislocation bands, and cross-slipping processes between {111} and {001} planes. A rationale for the observed mechanisms in terms of time-dependent damage processes will be discussed. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358832 Mon, 01 Feb 2010 00:00:00 +0100 3358832 http://www.medworm.com/index.php?rid=3358826&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000540%2Fabstract%3Frss%3Dyes [Fe–Co–Si (d)/native oxide]50 multilayer films with different metallic layer thicknesses were prepared on flexible substrates by DC magnetron sputtering. The films consisted of an amorphous phase with a small amount of nanocrystallites. All the films have a very high resistivity (higher than 10mΩcm), which is probably caused by the effect of the plastic substrate and the mixed amorphous and nanocrystalline structure. The permeability spectra show relatively high values of complex permeability and ferromagnetic resonance frequency up to 7.9GHz. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358826 Mon, 01 Feb 2010 00:00:00 +0100 3358826 http://www.medworm.com/index.php?rid=3358823&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000564%2Fabstract%3Frss%3Dyes Based on the thermodynamic extremal principle, a model for coarsening of intergranular precipitates in multicomponent systems is developed. The model provides the evolution equations for individual precipitates within the mean-field approach and generalizes the recent models applicable only to a special binary system. Simulations based on the model are performed for precipitates with the starting LSW size distribution, which changes after a certain time to a quasi-stationary one with a growth law, in agreement with recent models. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358823 Mon, 01 Feb 2010 00:00:00 +0100 3358823 http://www.medworm.com/index.php?rid=3358822&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000576%2Fabstract%3Frss%3Dyes The effect of the boundary conditions during uniaxial compression on the mechanical behavior of the Zr41.2Ti13.8Cu12.5Ni10Be22.5 metallic glass has been evaluated by using a pure Cu foil as a lubricant material between loading platens and specimens. The results reveal that the soft metal is very effective for reducing the contact friction at the platen–specimen interface, leading to a remarkable increase in plastic deformation with respect to more conventional semi-fluid lubricants. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358822 Mon, 01 Feb 2010 00:00:00 +0100 3358822 http://www.medworm.com/index.php?rid=3358820&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS135964621000059X%2Fabstract%3Frss%3Dyes Ductility, defined as the strain at the onset of necking, has been characterized in thin Al films using an on-chip, internal stress actuated, microtensile testing setup. In the smallest specimens, the ductility is equal to 0.08 and 0.27 for 200 and 375nm thick films, respectively, while the average strain-hardening exponents are, respectively, equal to 0.11 and 0.23. In addition to the thickness effect, ductility decreases with increasing specimen size due to imperfection sensitivity, involving a size-dependent statistical behaviour. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358820 Mon, 01 Feb 2010 00:00:00 +0100 3358820 http://www.medworm.com/index.php?rid=3358819&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000606%2Fabstract%3Frss%3Dyes Zr0.44Al0.56N1.20 films were deposited by reactive arc evaporation on WC–Co substrates. As-deposited films have a defect-rich NaCl-cubic and wurtzite phase mixture. During annealing at 1100°C the films undergo simultaneous recovery of the ZrN-rich c-ZrAlN nanoscale domains and formation of semicoherent w-ZrAlN nanobricks, while the excess nitrogen is released. This process results in an age hardening effect as high as 36%, as determined by nanoindentation. At 1200°C, the w-AlN recrystallizes and the hardening effect is lost. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358819 Mon, 01 Feb 2010 00:00:00 +0100 3358819 http://www.medworm.com/index.php?rid=3358817&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000539%2Fabstract%3Frss%3Dyes Solution nitriding was applied to type 304 stainless steel plate to make the austenite phase in the surface layer stable against cold rolling. Through this treatment, we could produce a structure-gradient stainless steel plate where an austenitic structure exists in the surface layer while a large fraction of deformation-induced martensitic structure is dispersed inside the plate. This surface-layer microstructure control significantly suppressed the permeation of hydrogen from the atomosphere owing to the low diffusivity of hydrogen in the stable austenitic surface layer. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358817 Mon, 01 Feb 2010 00:00:00 +0100 3358817 http://www.medworm.com/index.php?rid=3311568&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000527%2Fabstract%3Frss%3Dyes A generalized solute drag model for binary alloy solidification with a planar phase interface was proposed as an extension of Hillert–Sundman model. Using a new thermodynamic parameter set of the Si–As system, the present model can, with the introduction of three new adjustable parameters, fit the available experimental data of Si–9 at.% As alloy. In addition, non-solute drag models with the new set of thermodynamic parameters cannot reproduce the experimental data. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311568 Mon, 01 Feb 2010 00:00:00 +0100 3311568 http://www.medworm.com/index.php?rid=3216448&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000400%2Fabstract%3Frss%3Dyes (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216448 Thu, 28 Jan 2010 17:26:13 +0100 3216448 http://www.medworm.com/index.php?rid=3358833&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000333%2Fabstract%3Frss%3Dyes X-ray peak profiles are measured from individual bulk grains during tensile deformation. Two differently oriented copper samples pre-deformed in tension show the expected peak profile asymmetry caused by intra-grain stresses. One of the samples is oriented to achieve a significant change of the intra-grain stresses during in situ tensile loading and this is observed as a reversal of the sign of the peak profile asymmetry. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358833 Wed, 27 Jan 2010 00:00:00 +0100 3358833 http://www.medworm.com/index.php?rid=3358824&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000473%2Fabstract%3Frss%3Dyes Damping and Young’s modulus have been measured in single-phase Ti3Sn using resonant and dynamic mechanical techniques. The compound demonstrates unusual non-linear behavior. Elasticity decreases with strain, but increases with both frequency and temperature (343–673K); damping is unusually high and decreases with frequency, remains unchanged with strain and shows peaks at 190 and 310K. Although the mechanisms of energy dissipation are presently unknown, the results suggest the occurrence of a phase transition at about 350K. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358824 Mon, 25 Jan 2010 00:00:00 +0100 3358824 http://www.medworm.com/index.php?rid=3311567&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000515%2Fabstract%3Frss%3Dyes We report a surprising finding that the strain hardening at a constant strain rate and ambient temperature depends solely on the flow stress irrespective of the strain history. An important consequence of this observation is that the rate of generation of twins is controlled by the flow stress and is not an explicit function of strain. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311567 Mon, 25 Jan 2010 00:00:00 +0100 3311567 http://www.medworm.com/index.php?rid=3311566&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000485%2Fabstract%3Frss%3Dyes The effect of residual hydrogen, sorbed during the deposition process, on the hydrogenation behavior of ion-beam sputtered titanium thin films was investigated. Electromotive force and in situ stress measurements were conducted to study hydrogen absorption, phase boundaries and hydrogen-induced stress development in the Ti–H thin film system. Tests were conducted on both as-sputtered and previously discharged films; the effect of residual hydrogen is significantly manifested in the thermodynamic isotherms and stress–concentration curves. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311566 Mon, 25 Jan 2010 00:00:00 +0100 3311566 http://www.medworm.com/index.php?rid=3311565&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000503%2Fabstract%3Frss%3Dyes Various orientations and diffraction patterns of metastable β″ precipitates during artificial aging are investigated by means of high-resolution electron microscopy and electron diffraction in Al–Mg–Si alloys. Twelve orientations of β″ precipitates with C-centered monoclinic crystal structure are analyzed systematically. The orientation relationships can be expressed as: (010)β″//{100}Al; [001]β″//Al; [100]β″//Al. In addition, a new diffraction patterns model from β″ precipitates in 12 orientations is established under the [001]Al zone axis. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311565 Mon, 25 Jan 2010 00:00:00 +0100 3311565 http://www.medworm.com/index.php?rid=3311564&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000345%2Fabstract%3Frss%3Dyes Microstructural changes in NbF5-doped MgH2 during the dehydrogenation reaction (MgH2→Mg+H2) have been investigated by in situ heating transmission electron microscopy. Nanocrystalline MgH2 shows fast hydrogen sorption kinetics, as well as a high density of defects induced by high-energy ball milling. Since the network-structured Nb layer covering Mg grains acts both as an impediment to grain growth of Mg and a gateway for hydrogen diffusion by forming metastable NbH1−x, the improved kinetics can be maintained during hydrogen cycling. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311564 Mon, 25 Jan 2010 00:00:00 +0100 3311564 http://www.medworm.com/index.php?rid=3311563&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000357%2Fabstract%3Frss%3Dyes Molecular dynamics simulation was used to investigate reactions of a edge dislocation with interstitial dislocation loops of and 〈100〉 type in a model of iron. Whether loops are strong or weak obstacles depends not only on loop size and type, but also on temperature and dislocation velocity. These parameters determine whether a loop is absorbed on the dislocation or left behind as it glides away. Absorption requires glide of a reaction segment over the loop surface and cross-slip of dipole dislocation arms attached to the ends of the segment: these mechanisms depend on temperature and strain rate, as discussed here. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311563 Mon, 25 Jan 2010 00:00:00 +0100 3311563 http://www.medworm.com/index.php?rid=3311562&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000321%2Fabstract%3Frss%3Dyes True stress vs. true strain responses of Cu–6wt.% Al and Cu–12wt.% Mn alloys are presented. While Cu–6wt.% Al alloy shows the typical mechanical response of low stacking fault energy alloys, the Cu–12wt.% Mn alloy behaved similarly to medium to high stacking fault energy alloys. These findings clearly show that while short-range ordering triggers slip planarity, it has a minor effect on total dynamic recovery of these copper alloys. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311562 Thu, 21 Jan 2010 00:00:00 +0100 3311562 http://www.medworm.com/index.php?rid=3294508&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS135964621000031X%2Fabstract%3Frss%3Dyes A recent comment on a previously published paper addressed the invalid explanation of the off-diagonal interdiffusion coefficients of the β-Ni(Al,Cr) phase in the Ni–Cr–Al system according to the symmetric property of the thermodynamic matrix. In this paper, the experimental data presented by Hou et al. was reanalyzed and the interdiffusion coefficient matrix was estimated again. The results of the analysis have been discussed in terms of a brief reply to the comments of Liu and Liang. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294508 Thu, 21 Jan 2010 00:00:00 +0100 3294508 http://www.medworm.com/index.php?rid=3311561&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000291%2Fabstract%3Frss%3Dyes We introduce a synthesis method in which liquid metals in an emulsion mix and solidify under the influence of ultrasound radiation. We use it to produce two types of metallic nano- and microparticles. The first group, formed by rapid droplet solidification, is characterized by a nearly perfect spherical shape. The second group consists of hollow particles which were probably formed by near-adiabatic cooling of the metal inside an expanding cavitation bubble. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311561 Mon, 18 Jan 2010 00:00:00 +0100 3311561 http://www.medworm.com/index.php?rid=3311560&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS135964621000028X%2Fabstract%3Frss%3Dyes We report the low temperature coefficient of resistivity (TCR) of antiperovskite Mn3NiN compound for the first time. Interestingly, the resistivity remained almost constant with temperature from 250K. The dρ/dT value and the TCR were determined to be about 7.17×10−8ΩcmK−1 and 12.3×10−5K−1, respectively. It was found that the low TCR behavior was related to the magnetic transition and large lattice contraction. The origin of low TCR behavior was further analyzed based on the Labbé–Jardin tight-binding approximation model. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311560 Mon, 18 Jan 2010 00:00:00 +0100 3311560 http://www.medworm.com/index.php?rid=3311559&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000242%2Fabstract%3Frss%3Dyes We have found that a better glass former can be obtained in the Zr–Cu binary alloys with high oxygen content. However, the best glass former is shifted to different composition as oxygen content changes. Our findings provide an important insight into the mechanism of the oxygen on glass formation, which is a useful guideline for designing new BMGs with low-grade materials and low processing cost. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311559 Mon, 18 Jan 2010 00:00:00 +0100 3311559 http://www.medworm.com/index.php?rid=3311558&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000254%2Fabstract%3Frss%3Dyes The intrinsic plasticity of Zr44Ti11Cu9.8Ni10.2Be25 and Zr55Ti5Al10Cu20 Ni10 bulk metallic glasses (BMGs) are improved from 0.5% up to 15% plastic strain due to the introduction of microstructural inhomogeneities upon cold rolling at room temperature. This approach shows an easy way to overcome the intrinsic brittleness of the BMGs by modifying their physical properties, which enables easy nucleation and branching of multiple shear bands upon unconstrained loading during the compression test. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311558 Mon, 18 Jan 2010 00:00:00 +0100 3311558 http://www.medworm.com/index.php?rid=3311557&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000266%2Fabstract%3Frss%3Dyes For a long time, the determination of free volume has been a challenging problem in research on metallic glasses. An approach to determine quantitatively the free volume of metallic glasses from enthalpy measurements and calibration with the equilibrium free volume was developed and validated for as-cast and annealed Pd40Ni40P20 bulk metallic glasses. The free volume change with annealing time is in good agreement with that calculated theoretically from the free volume annihilation kinetics and that deduced from the density measurement results. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311557 Mon, 18 Jan 2010 00:00:00 +0100 3311557 http://www.medworm.com/index.php?rid=3311551&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000175%2Fabstract%3Frss%3Dyes The texture in a polycrystalline Ni50Mn29Ga21 magnetic shape-memory alloy deformed by high-pressure torsion (HPT) at 1173K was investigated with high-energy synchrotron radiation. HPT changed the extrusion texture to a predominant slightly rotated cube {001} 〈100〉 and a weak F {110}〈100〉 component. During HPT the grain structure coarsened. Phase transformations during cooling from the deformation temperature led to coarse and fine sets of martensitic twin variants. The results are discussed with respect to deformation mode, grain growth and phase transformations. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311551 Mon, 18 Jan 2010 00:00:00 +0100 3311551 http://www.medworm.com/index.php?rid=3311556&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000230%2Fabstract%3Frss%3Dyes An Fe–1.0C–17Cr (wt.%) stainless steel was subjected to subzero treatment to investigate the structure of the martensite midrib. During the course of the isothermal holding in liquid nitrogen (−196°C), the thin-plate martensite formed first, and lenticular martensite later. The substructures of thin-plate martensites and lenticular martensite were examined using transmission electron microscopy, focusing on the details of the midrib. The results provide strong evidence to suggest that thin-plate martensite can be transformed into lenticular martensite. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311556 Fri, 15 Jan 2010 00:00:00 +0100 3311556 http://www.medworm.com/index.php?rid=3311555&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000229%2Fabstract%3Frss%3Dyes Initial {10−12} twin influenced the plastic deformation mechanism activated during fatigue deformation, especially during compressive loading, by enhancing the activity of the detwinning mechanism. With the aid of initial {10−12} twin, compressive deformation could be fully accommodated by detwinning alone. This change in the predominant plastic deformation mechanism during compressive loading significantly decreased compressive flow stress, causing an increase in mean stress, and thus deteriorated the fatigue resistance of the material. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311555 Fri, 15 Jan 2010 00:00:00 +0100 3311555 http://www.medworm.com/index.php?rid=3311554&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000217%2Fabstract%3Frss%3Dyes Highly luminescent and weak ferromagnetic ZnO nanorods were prepared by a facile solvothermal method. Luminescence studies carried out on as-synthesized ZnO nanorods, subjected to heat treatment in a variety of environments, established that Zn vacancies are responsible for the green emission. A significant change in morphology has been found on treating these as-synthesized nanorods in hydrogen, even at room temperature, which is attributed to the removal of oxygen from the already Zn-deficient ZnO lattice. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311554 Fri, 15 Jan 2010 00:00:00 +0100 3311554 http://www.medworm.com/index.php?rid=3311553&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000205%2Fabstract%3Frss%3Dyes Fast sintering processes offer promising new routes for the fabrication of bulk ceramics but it is not clear that the microstructural details and properties resulting from a very short, rapid densification procedure are the same in all respects as those resulting from traditional sintering. Here, not fully relaxed grains and their weak mechanical properties of as-prepared nanoscale alumina are described. It was found that low temperature annealing did not cause grain growth but allowed normal boundaries to develop. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311553 Fri, 15 Jan 2010 00:00:00 +0100 3311553 http://www.medworm.com/index.php?rid=3311552&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000187%2Fabstract%3Frss%3Dyes Using first-principles density-functional calculations of the total energy, we performed a systematic study of the diffusion activation energies of O2 and CO in SiO2 and Si1−xCxO2. Our results suggest that the dense Si1−xCxO2 (e.g., Si2CO6) layer may play a critical role in the SiC thermal oxidation process. The out-diffusion of CO through SiO2 or Si2CO6 is the controlling step of the SiC thermal oxidation. Known experimental data are explained well by our results. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311552 Thu, 14 Jan 2010 00:00:00 +0100 3311552 http://www.medworm.com/index.php?rid=3166958&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209008203%2Fabstract%3Frss%3Dyes (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3166958 Wed, 13 Jan 2010 16:43:38 +0100 3166958 http://www.medworm.com/index.php?rid=3311570&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000138%2Fabstract%3Frss%3Dyes We recently published a short paper on modelling DSC curves of AA 2024-T351 to which Starink and Wang have made a number of critical comments. We recognize that some features of our paper were not fully developed initially and we now appreciate the opportunity of clarifying these points. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311570 Wed, 13 Jan 2010 00:00:00 +0100 3311570 http://www.medworm.com/index.php?rid=3311569&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS135964621000014X%2Fabstract%3Frss%3Dyes With several fitted model parameters, the Kampmann–Wagner (KW) model can be made to fit a differential scanning calorimetry curve of an Al–Cu–Mg alloy fairly well. However, this procedure will generally not be able to provide predictions of the coarsening kinetics of the precipitates. Past work has shown that a KW model can only work if the interfacial energy in the coarsening stage is much higher than that in the nucleation and growth stage. The KW model fails to accurately predict the impingement stage of the precipitation reaction. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311569 Wed, 13 Jan 2010 00:00:00 +0100 3311569 http://www.medworm.com/index.php?rid=3311550&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000151%2Fabstract%3Frss%3Dyes The interfacial energies of twin boundaries and stacking faults in metal magnesium have been calculated using first-principles supercell approach. Four types of twin boundaries and two types of stacking faults are investigated, namely, those due to the () mirror reflection, the () mirror glide, the () mirror reflection, the () mirror glide, the I1 stacking fault and the I2 stacking fault. The effects of supercell size on the calculated interfacial energies are examined. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311550 Wed, 13 Jan 2010 00:00:00 +0100 3311550 http://www.medworm.com/index.php?rid=3311549&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000163%2Fabstract%3Frss%3Dyes We observed very bright orange–red light emissions from amorphous silicon nitride prepared under high-pressure deposition conditions. By increasing the pressure from 300 to 700Pa, the photoluminescence (PL) intensity could be more than doubled. The introduction of N–H bonds is shown to play a key role in enhancing the PL intensity of the films. The improved PL intensity is attributed to the good hydrogen passivation of nonradiative defect states related to N under high growth pressures. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311549 Wed, 13 Jan 2010 00:00:00 +0100 3311549 http://www.medworm.com/index.php?rid=3294497&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209008136%2Fabstract%3Frss%3Dyes The mean free path length for dislocation movement during deformation of a polycrystal determines the storage term during strain hardening. The classical Mecking–Estrin (ME) model postulates additivity of the effects of substructure and grain boundaries. The present work considers the probability distribution of obstacles along the path and uses the laws of probability to derive an expression of which the ME model is a good approximation. The physical implications of the approach and the extension of this method to particle hardening are briefly discussed. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294497 Wed, 13 Jan 2010 00:00:00 +0100 3294497 http://www.medworm.com/index.php?rid=3311548&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000114%2Fabstract%3Frss%3Dyes We compare the dislocation substructure within macrozone and non-macrozone regions of hot-rolled Ti–6Al–4V. Hough-based and cross-correlation-based analysis of electron backscatter diffraction (EBSD) patterns are used to establish the grain orientations and intra-granular misorientations, respectively. The set of geometrically necessary dislocations (GNDs) that support measured lattice curvatures and minimize the total GND line energy are calculated. The GND content in the macrozone is approximately twice that in the non-macrozone region, and 〈a〉 GNDs are present at densities ∼10 times higher than 〈c+a〉 GNDs. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311548 Mon, 11 Jan 2010 00:00:00 +0100 3311548 http://www.medworm.com/index.php?rid=3311547&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000059%2Fabstract%3Frss%3Dyes Surfaces of bulk glassy Zr59Ti3Cu20Al10Ni8 samples were shot-peened for different times and their corrosion behaviour was tested in 0.01M Na2SO4+xM NaCl (x=0; 0.01; 0.1) and 6M HCl. Slight improvement of spontaneous passivity but a decrease of pitting resistance are detected with prolonged shot-peening duration. The corrosion damage evolution is governed by the nature of the mechanically generated defects and their surrounding stress fields. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3311547 Mon, 11 Jan 2010 00:00:00 +0100 3311547 http://www.medworm.com/index.php?rid=3294506&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000102%2Fabstract%3Frss%3Dyes The ideal tensile and shear strengths of TiB2, ZrB2 and HfB2 have been investigated by first-principles stress–strain calculations. Among the studied diborides, TiB2 unexpectedly exhibits the weakest shear strength in the (0001) basal plane, comparable to that of ZrB2 and HfB2 in the {} prismatic planes. Due to the nonlinearity of the stress response at large stains, the plastic anisotropy cannot be derived from elastic constants. Based on the relative stiffness of boron hexagons, a bond length indicator is obtained to characterize the preference for basal or prismatic slip in diborides. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294506 Mon, 11 Jan 2010 00:00:00 +0100 3294506 http://www.medworm.com/index.php?rid=3294505&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000096%2Fabstract%3Frss%3Dyes The interdiffusion coefficient in Ni(Mo) solid solution, impurity diffusion of Mo in Ni, average interdiffusion coefficient of the NiMo–σ phase and activation energies for diffusion in solid solution and in the σ phase of the Ni–Mo binary system are evaluated through the diffusion couple approach. These results are utilized to identify the possible diffusion mechanism. Low activation energy in the σ phase indicates a grain-boundary-controlled diffusion process. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294505 Mon, 11 Jan 2010 00:00:00 +0100 3294505 http://www.medworm.com/index.php?rid=3294504&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000126%2Fabstract%3Frss%3Dyes We present the first direct experimental evidence of two-length-scale phase transition kinetics in this alloy system. It was further found that aging in the R-phase leads to two-way memory “loss”, characterized by the reselection of new variants. We attributed this two-way memory “loss” to the internal stresses caused by the defects formed in the off-equilibrium state of the studied AuCd system. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294504 Mon, 11 Jan 2010 00:00:00 +0100 3294504 http://www.medworm.com/index.php?rid=3294503&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000035%2Fabstract%3Frss%3Dyes The addition of Cr to (Mo0.85Nb0.15)Si2 crystals significantly improves the thermal stability of the lamellar structure composed of C11b–MoSi2 and C40–NbSi2 phases. Analysis using electron microscopy indicates the segregation of Cr atoms at the C40/C11b lamellar interface. This leads to a decrease in the lattice misfit strain at the interface and better thermal stability of the lamellae. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294503 Mon, 11 Jan 2010 00:00:00 +0100 3294503 http://www.medworm.com/index.php?rid=3294502&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000060%2Fabstract%3Frss%3Dyes The magnetoelectric ceramic composite formed by Pb0.988(Zr0.52Ti0.48)0.976Nb0.024O3 (PZTN) and CoFe2O4 (CF) was prepared in situ by citrate–nitrate combustion on the PZTN powder template. The electromagnetic properties showing double negative resonance with negative values of dielectric permittivity εr and magnetic permeability μr, in a close frequency range of 2×108Hz to 2.6×109Hz, are reported. In addition, the condition of impedance matching with free space is accomplished at the frequency f=280MHz in these ceramic composites. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294502 Mon, 11 Jan 2010 00:00:00 +0100 3294502 http://www.medworm.com/index.php?rid=3294501&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000047%2Fabstract%3Frss%3Dyes The room temperature plane strain channel die compression behavior of a 99.99% Al {110}“brass” orientation embedded in a {110}“Goss” orientation was compared to a deformed brass single crystal orientation. The average lattice position in the embedded brass orientation was found to rotate towards the “S” orientation, unlike the stable brass single crystal orientation. Interaction-induced activation of a secondary slip system in the embedded brass orientation was found to contribute to the texture instability. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294501 Mon, 11 Jan 2010 00:00:00 +0100 3294501 http://www.medworm.com/index.php?rid=3294500&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000084%2Fabstract%3Frss%3Dyes Alumina ceramic with controlled porosity and small pore sizes of (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294500 Mon, 11 Jan 2010 00:00:00 +0100 3294500 http://www.medworm.com/index.php?rid=3294499&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000072%2Fabstract%3Frss%3Dyes This paper investigates the effect of vacancies on dislocation nucleation in iron by means of molecular dynamics atomistic simulations at low temperatures. Increasing the vacancy concentration resulted in a decrease in the load at the onset of plasticity following a power law relationship. Dislocations did not nucleate at a vacancy in these simulations. This suggests that vacancies, even without diffusing within the solid, may impact experimental observations of dislocation nucleation using nanoindentation. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294499 Mon, 11 Jan 2010 00:00:00 +0100 3294499 http://www.medworm.com/index.php?rid=3294498&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646210000023%2Fabstract%3Frss%3Dyes Single-phase nanocrystalline SmCo7 bulk alloy with an ultrafine grain structure was prepared using a novel fabrication route that combines induction melting, ball milling and spark plasma sintering. The nanocrystalline SmCo7 was formed in the hexagonal TbCu7-type crystal structure. It was discovered that the single-phase nanocrystalline SmCo7 alloy has excellent magnetic properties. The influences of the lattice characteristics and the nanograin structure on the magnetic performance of this alloy were analyzed. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294498 Fri, 08 Jan 2010 00:00:00 +0100 3294498 http://www.medworm.com/index.php?rid=3294494&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209008112%2Fabstract%3Frss%3Dyes The mechanical properties of laser-surface-alloyed AZ91, a magnesium-based alloy (Mg–9Al–0.9Zn) with nickel, were determined. Laser surface alloying was carried out using a continuous wave CO2 laser under optimum process parameters. Laser surface alloying led to the formation of a dispersion of intermetallics of Mg and Ni (MgNi2) in a magnesium matrix with an improved Young’s modulus (45–85GPa, as compared to the 45GPa of as-received substrate) and improved wear resistance. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294494 Mon, 04 Jan 2010 00:00:00 +0100 3294494 http://www.medworm.com/index.php?rid=3294482&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209008124%2Fabstract%3Frss%3Dyes The stress–strain response, slip mechanisms and size effect in Mg (0001) single crystal was investigated by microcompression testing. It is found that plasticity occurs relatively homogeneously up to a critical stress, at which point a massive deformation occurs. While the yield stress increases with decreasing diameter, the qualitative behavior is independent of column size. Cross-sectional electron back-scattered diffraction measurements show that twinning is not the predominant deformation mechanism. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294482 Mon, 04 Jan 2010 00:00:00 +0100 3294482 http://www.medworm.com/index.php?rid=3294496&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209008069%2Fabstract%3Frss%3Dyes We report the use of an energetic criterion to assess the deformability of glassy alloys based on the cooperative shearing model and energy landscape theory. The barrier energy density necessary for the activation of shear transformation zones and the initiation of shear bands shows a strong correlation with the ductility of bulk metallic glasses. This finding directly ties the ductility of metallic glasses to the forming ability of shear bands and offers an energetic insight into the mechanical behavior of metallic glasses. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294496 Thu, 31 Dec 2009 00:00:00 +0100 3294496 http://www.medworm.com/index.php?rid=3294495&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209008094%2Fabstract%3Frss%3Dyes The hydrogen permeation behavior of Cu–15 vol.% Nb and Cu–20 vol.% Nb alloys which were developed originally for superconducting wires has been investigated. Both the alloys with a microstructure consisting of body-centered cubic Nb (bcc-Nb) filaments and a face-centered cubic Cu matrix exhibited a hydrogen permeability of ∼2×10−9molm−1s−1Pa−0.5 at 673K. The samples tested are resistant to hydrogen embrittlement despite the fact that bcc-Nb is susceptible to hydrogen embrittlement. Our work demonstrates that Nb-based multifilamentary alloys are potential candidates for alloy membranes for hydrogen purification. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294495 Thu, 31 Dec 2009 00:00:00 +0100 3294495 http://www.medworm.com/index.php?rid=3294493&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209008057%2Fabstract%3Frss%3Dyes Simple mechanochemical procedures can be used for the solid-state preparation of stable complex aluminium hydrides as hydrogen storage materials. For the synthesis of unstable complex hydrides, cryomilling at temperatures at which product decomposition does not take place under milling conditions appears to be a viable method. To probe the potential of cryomilling for the synthesis of complex aluminium hydrides, the reactions of different alkaline hydrides with AlH3 were tested under these conditions. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294493 Thu, 31 Dec 2009 00:00:00 +0100 3294493 http://www.medworm.com/index.php?rid=3294492&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209008100%2Fabstract%3Frss%3Dyes We report an intriguing observation that the interaction of brittle nanoscale periodic corrugations (NPCs) can lead to the formation of ductile dimples on the dynamic fracture surface of a tough Vit 1 bulk metallic glass (BMG) under high-velocity plate impact. A “beat” phenomenon due to superposition of simple harmonic vibrations, approximately characterizing NPCs, is proposed to explain this unusual brittle-to-ductile transition. The present results agree well with our previously revealed energy dissipation mechanism in the fracture of BMGs. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294492 Thu, 31 Dec 2009 00:00:00 +0100 3294492 http://www.medworm.com/index.php?rid=3294491&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209008082%2Fabstract%3Frss%3Dyes The formation of Ni silicide alloyed with Pt has been analyzed by atom probe tomography. A 300°C/1h anneal results in simultaneous growth of the NiSi and Ni2Si phases: the Ni2Si phase is a continuous layer with columnar grains, while the NiSi phase forms a discontinuous layer. Direct evidence of Pt diffusion short-circuits via Ni2Si grain boundaries is shown. The presence of Pt in the grains and interphase boundaries may explain the change in the Ni silicide formation for the Ni(5% Pt)/Si system. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294491 Thu, 31 Dec 2009 00:00:00 +0100 3294491 http://www.medworm.com/index.php?rid=3294490&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209008070%2Fabstract%3Frss%3Dyes Much work has been carried out over the past 40years on the oxidation of zirconium alloys used for nuclear fuel cladding, but there is no consensus as to the critical factors that control kinetics, even though this is vital for the design of materials for higher burn-up regimes. One unanswered question is the role of porosity in controlling oxidation. Here we show that the nature of the nanoscale porosity can be correlated to different stages of the oxidation process. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294490 Thu, 31 Dec 2009 00:00:00 +0100 3294490 http://www.medworm.com/index.php?rid=3294489&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209008045%2Fabstract%3Frss%3Dyes Welding of copper foils (150μm thick) achieved at room temperature by very high power ultrasonic additive manufacturing was seen to involve appreciable softening and enhanced plastic flow. The initial coarse-grained structure (25μm) in the material changed into fine dynamically recrystallized grains (0.3–10μm) at the foil interface within the order of a few milliseconds of processing. This phenomenon led to metallurgical bonding through grain boundary migration and allowed for successive welding of tapes to form a three-dimensional part. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294489 Wed, 30 Dec 2009 00:00:00 +0100 3294489 http://www.medworm.com/index.php?rid=3120340&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007854%2Fabstract%3Frss%3Dyes (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120340 Fri, 25 Dec 2009 16:15:50 +0100 3120340 http://www.medworm.com/index.php?rid=3294488&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209008021%2Fabstract%3Frss%3Dyes We demonstrate that the origin of twinning in the Mg alloy Mg–3Al–1Zn can be understood and technologically manipulated from the atomic viewpoint. By using electron backscattered diffraction, we identify the species of twins in the compressed alloy. A theoretical analysis based on quadrangular prism-shaped atomic group unit model attributes the atomic motion during twinning to the rotation of units. Moreover, we find that the degree of difficulty for twinning in Mg alloy is governed by the magnitude of the relative motion between adjacent units. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294488 Fri, 25 Dec 2009 00:00:00 +0100 3294488 http://www.medworm.com/index.php?rid=3294487&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209008008%2Fabstract%3Frss%3Dyes This paper presents results of an investigation of the neck growth kinetics during microwave sintering of free-packed copper powder. Application of the classical sphere-to-sphere approach showed similarities between microwave and conventional sintering processes for long soaking times. Anomalous neck growth during the initial stage of microwave sintering was also revealed, which might be caused by a non-conventional diffusion mechanism. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294487 Fri, 25 Dec 2009 00:00:00 +0100 3294487 http://www.medworm.com/index.php?rid=3294486&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209008033%2Fabstract%3Frss%3Dyes Microsheets 50μm thick consisting of DC01 steel were investigated in cold-worked initial state as well as after different heat treatments. Uniaxial tensile tests were carried out and grain size distributions were determined. The best properties with respect to micro cold forming were achieved after annealing for 30min at 850°C. These samples show a significant grain coarsening to about 18μm in diameter. The elongation at maximum load Ag is increased to 16%. Moreover, the thickness of the sheets causes an unusual decrease in yield strength compared to the Hall–Petch relation. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294486 Fri, 25 Dec 2009 00:00:00 +0100 3294486 http://www.medworm.com/index.php?rid=3294485&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS135964620900801X%2Fabstract%3Frss%3Dyes Based upon a thermodynamic approach, maps are constructed to study spreading during the initial stage of liquid-phase sintering. The maps are diagrams with contact angle as one axis and critical liquid-to-solid particle radius ratio as the other, showing the fields of spreading and no spreading. Separating the fields are contours of constant packing factor. The potentials of the maps are also explored. One use of the maps is to determine the contact angle between liquid binder and solid hard phases. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294485 Fri, 25 Dec 2009 00:00:00 +0100 3294485 http://www.medworm.com/index.php?rid=3216472&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007994%2Fabstract%3Frss%3Dyes The strain-rate sensitivity of V–5Cr–5Ti alloy was investigated in the strain-rate range 10−4–10−1s−1 at room temperature. The rate sensitivity decreased with the increase of plastic strain, which was qualitatively explained by dislocation thermal activation theory combined with a dislocation multiplication model. A modified Johnson–Cook model was developed to characterize the strain-rate dependence. Scanning electron microscopy of the fracture surfaces revealed that the dominant mechanisms of fracture were intergranular fracture and dimple rupture. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216472 Fri, 25 Dec 2009 00:00:00 +0100 3216472 http://www.medworm.com/index.php?rid=3216471&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007957%2Fabstract%3Frss%3Dyes A photoconductive semiconductor switch (PCSS) based on an individual ZnS nanobelt (NB) was investigated. Under ultraviolet light (280nm), the current–voltage curve shows that this PCSS is of high photosensitivity (∼104), and the response time spectrum shows that this PCSS has a fast response (typical rise time 0.07s and decay time 0.12s) and a high-voltage response (6.7V). Oxygen chemisorption is responsible for the improved photoconductive properties. This PCSS is a promising candidate for future integration. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216471 Mon, 21 Dec 2009 00:00:00 +0100 3216471 http://www.medworm.com/index.php?rid=3216470&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007933%2Fabstract%3Frss%3Dyes Ga14N and Ga15N were grown to study the isotopic effect on GaN lattice constants and band gap energy. It was shown that Ga15N has smaller lattice constants a and c at room temperature. However, the thermal expansion coefficients of Ga15N are larger than those of Ga14N up to 600°C. Photoluminescence at 4.5–50K implies a wider band gap in Ga15N, presumably due to its smaller unit cell at low temperature, and a weaker band gap renormalization effect via phonon–electron interaction. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216470 Mon, 21 Dec 2009 00:00:00 +0100 3216470 http://www.medworm.com/index.php?rid=3216469&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007945%2Fabstract%3Frss%3Dyes To avoid ferromagnetic hysteresis losses in alternating current applications of thin film superconductors, paramagnetic substrates are required at 77K, the operating temperature of the superconducting YBa2Cu3O7−x. Therefore the composition is modified starting from Ni5W to reduce the ferromagnetic Curie temperature. This temperature can be suppressed well below 77K by adding Cr or further W to the alloys. It is shown that the Ni–W–Cr tapes can be processed, leading to at least 90% cube texture. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216469 Mon, 21 Dec 2009 00:00:00 +0100 3216469 http://www.medworm.com/index.php?rid=3216468&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007921%2Fabstract%3Frss%3Dyes The strength of dislocation junctions with segments of unequal length is studied. Such structures are common, while the equivalent symmetric junctions are exceptions. It is shown that varying the length of junction “arms” leads to significant variation of the junction strength and to changes of the failure mechanism. The relative strength of Lomer and glissile junctions may be reversed as the junctions become asymmetric. This increases the variability of the strength of pinning sites a mobile dislocation encounters during glide. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216468 Mon, 21 Dec 2009 00:00:00 +0100 3216468 http://www.medworm.com/index.php?rid=3216467&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007805%2Fabstract%3Frss%3Dyes A benign and facile process for forming monodisperse, hollow porous silica shells of a novel cubic morphology is identified. Templated on monodisperse crystalline germania cores that can be removed via aqueous dissolution, the hollow shells and their core–shell precursors are amenable to assembly into highly porous, gap-free near-monolayer films through manual and evaporative assembly techniques. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216467 Thu, 17 Dec 2009 00:00:00 +0100 3216467 http://www.medworm.com/index.php?rid=3294484&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007787%2Fabstract%3Frss%3Dyes Corrosion resistance and fatigue performance of Vitreloy glasses with low fractions of late transition metals (LTMs) in 0.6M NaCl are investigated and compared to a traditional Vitreloy glass and other crystalline alloys. Owing to their ability to form uniform passive films, low LTM Vitreloy glasses exhibit corrosion rates that are an order of magnitude lower than those of other alloys considered. The fatigue ratios in solution are substantially lower than crystalline alloys considered and similar to traditional Vitreloy glasses, which fail at low stresses due to limited repassivation in solution. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294484 Wed, 16 Dec 2009 00:00:00 +0100 3294484 http://www.medworm.com/index.php?rid=3216466&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007799%2Fabstract%3Frss%3Dyes Thermally activated dislocation dynamics in austenitic FeMnC steels is investigated based on a collection of tensile yield stresses at different temperatures and strain rates of numerous steels available in the literature. A classical viscoplastic potential is suitable to describe the phenomena in binary FeMn alloys. The description of ternary FeMnC alloys is more complex as two basic mechanisms should be involved. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216466 Wed, 16 Dec 2009 00:00:00 +0100 3216466 http://www.medworm.com/index.php?rid=3216465&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007775%2Fabstract%3Frss%3Dyes Nanograined Co and Fe–Ni films with low levels of defects and impurities were prepared by pulse electrodeposition. The significant reduction in the onset temperature of phase transformation upon heating in nanograined Co and Fe–Ni indicates that these phase transformations are greatly promoted by grain growth, which in turn reduces the thermal stability of the low-temperature-phases ε-Co and α-FeNi. The abnormal stability of the high-temperature phase γ-Co may be attributed to the inhibition of the nanoscale twin boundaries caused by annealing. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216465 Wed, 16 Dec 2009 00:00:00 +0100 3216465 http://www.medworm.com/index.php?rid=3216464&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007763%2Fabstract%3Frss%3Dyes Focused ion beam machined compression pillars created from [111], [001] and [210] NiTi demonstrate that orientation plays a dominant role in determining dislocation flow stress in stress-induced martensite. This is in contrast to bulk NiTi in which martensite strength is primarily dictated by precipitate size. Post-mortem transmission electron microscopy and Laue microdiffraction measurements reveal respectively dense dislocation structures and stabilized martensite consistent with bulk observations in heavily deformed NiTi. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216464 Wed, 16 Dec 2009 00:00:00 +0100 3216464 http://www.medworm.com/index.php?rid=3216463&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007751%2Fabstract%3Frss%3Dyes Discrete relaxation events on the submicron scale were observed during nanoindentation on polyethylene. The frequency with which these events occur increases as the crystallinity of the polyethylene increases, but the effect saturates at high crystallization levels. At a given crystallinity, the occurrence frequency decreases as temperature increases, due possibly to the enhancement of viscous flow as a competing stress relaxation process. The emission rate of the discrete relaxation events also increases with temperature, exhibiting an activation energy of about 0.22eV. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216463 Tue, 15 Dec 2009 00:00:00 +0100 3216463 http://www.medworm.com/index.php?rid=3216457&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007714%2Fabstract%3Frss%3Dyes Porous Al2O3–ZrO2 composites with homogeneous and long-range ordered channels were produced by an ice template method. An increase of the initial solids loading from 40 to 70wt.% caused the final porosity to decrease from 74% to 35%, while the compressive strength increased from 15 to 81MPa. The sample obtained from the 80wt.% suspension was not porous, and a critical velocity model is employed to explain this phenomenon. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216457 Tue, 15 Dec 2009 00:00:00 +0100 3216457 http://www.medworm.com/index.php?rid=3294483&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007702%2Fabstract%3Frss%3Dyes Single-crystal magnesium micropillars are fabricated using focused ion beam (FIB) milling. The micropillars are loaded in compression along the [0001] c-axis. The stress–strain curves from these microcompression experiments reveal significant strain hardening, and post-mortem microscopy reveals traces of pyramidal slip on the deformed specimens. Transmission electron microscopy (TEM) specimens are excised from the micropillars using FIB, and TEM analysis confirms the presence of pyramidal dislocations as well as 〈c〉 dislocations. No twinning is observed. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294483 Mon, 14 Dec 2009 00:00:00 +0100 3294483 http://www.medworm.com/index.php?rid=3216462&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS135964620900774X%2Fabstract%3Frss%3Dyes The interaction between Ni3Si and Zn at 500°C was investigated. The periodically layered structure was determined by using a combination of X-ray diffraction and scanning electron microscopy with energy-dispersive spectroscopy. A general qualitative description describing the nucleation process of this periodically layered structure is presented. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216462 Mon, 14 Dec 2009 00:00:00 +0100 3216462 http://www.medworm.com/index.php?rid=3216461&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007696%2Fabstract%3Frss%3Dyes Fatigue coaxing experiments were conducted on a Zr-based bulk-metallic glass using three-point bending at room temperature following the generation of an S/N curve under conventional testing methods at R=0.1. Each new specimen was cyclically loaded initially just below the fatigue limit for different numbers of cycles prior to increasing the mean stress in increments of 15–25MPa after each additional cycle increment until the sample failed. Possible implications and source(s) of the increased fatigue limit are discussed. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216461 Mon, 14 Dec 2009 00:00:00 +0100 3216461 http://www.medworm.com/index.php?rid=3216460&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007684%2Fabstract%3Frss%3Dyes Based on the free volume model, a critical value of reduced free volume is proposed to be the sufficient condition for the onset of yielding in metallic glasses. The corresponding stress for the onset of yielding is found to be less than the macroscopically measured yield strength, which is consistent with experimental observations. The difference in deformability between brittle and plastic metallic glasses can be explained in terms of the free volume evolution in the localized shear zone. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216460 Mon, 14 Dec 2009 00:00:00 +0100 3216460 http://www.medworm.com/index.php?rid=3216459&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007672%2Fabstract%3Frss%3Dyes The fatigue crack growth behavior of a Zr44Ti11Ni10Cu10Be25 bulk metallic glass (BMG) was measured in an inert dry N2 environment. When compared to results measured in ambient air, the present results showed a higher fatigue threshold and lower crack growth rates in the near-threshold region. Such results reveal that there is a significant effect of ambient air in accelerating fatigue crack growth for this BMG. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216459 Mon, 14 Dec 2009 00:00:00 +0100 3216459 http://www.medworm.com/index.php?rid=3166986&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007726%2Fabstract%3Frss%3Dyes Two hierarchically porous silica ceramics with unidirectionally aligned channel morphology have been in situ synthesized by using soluble starch monoliths with well-defined uniaxial macroporous structure as template. Both these ceramics faithfully inherit the structure of soluble starch templates and show a large BET surface as well as a microstructure of uniform worm-like nanopores and a lamellar phase. These materials may be suitable for use in various separation and reaction processes. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3166986 Mon, 14 Dec 2009 00:00:00 +0100 3166986 http://www.medworm.com/index.php?rid=3166985&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007738%2Fabstract%3Frss%3Dyes Predominantly single-phase Hf2[Al(Si)]4C5 ceramic has been fabricated by an in situ reaction/hot-pressing method using Hf, Al, Si and graphite as starting materials. Hf2[Al(Si)]4C5 shows comparable mechanical properties to Zr2[Al(Si)]4C5, and lower hardness and stiffness but higher strength and toughness than HfC. The stiffness decreases slowly with temperature and at 1600°C it remains 83% of that at ambient temperature. Compared to Zr2[Al(Si)]4C5 and HfC, however, Hf2[Al(Si)]4C5 exhibits a relatively higher coefficient of thermal expansion, an intermediate specific heat capacity and a lower thermal conductivity. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3166985 Mon, 14 Dec 2009 00:00:00 +0100 3166985 http://www.medworm.com/index.php?rid=3216458&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007659%2Fabstract%3Frss%3Dyes The same section of deformed and annealed Al–0.1wt.% Mn has been characterized by high-resolution electron backscattered diffraction to determine cube recrystallization nucleation. After 90% plane strain compression, two types of deformed cube segments were present in the microstructure: (i) thin segments along the rolling direction (RD) as “narrow transition bands” between grains; and (ii) fragmented bands inclined about 15° to the RD as “strain localizations” inside grains. On light annealing, cube grains were preferentially nucleated along the intergranular RD segments. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216458 Thu, 10 Dec 2009 00:00:00 +0100 3216458 http://www.medworm.com/index.php?rid=3216456&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007660%2Fabstract%3Frss%3Dyes We demonstrate that irradiation may enhance the plasticity in metallic glasses by increasing the free-volume content via micropillar compression experiments on an ion-irradiated bulk metallic glass (BMG). Results show that irradiation decreases the flow stress and enhances the shear band formation by lowering the magnitude of stress serrations in plastic flow regime. These results highlight that amorphous alloys can mitigate the deleterious affects of severe ion irradiation as compared to their crystalline counterparts. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216456 Thu, 10 Dec 2009 00:00:00 +0100 3216456 http://www.medworm.com/index.php?rid=3216455&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007647%2Fabstract%3Frss%3Dyes The Frank–Bilby equation has been utilized to develop a general approach in which a simple criterion is proposed to classify interfaces with discrete misfit dislocation arrays into four types so that these misfit dislocation arrays can be conveniently characterized with uniform formulae. The relation connecting misfit dislocation configurations with the matrices in the Frank–Bilby equation, the special interfaces consistent with the Δg-parallelism and the continuity of misfit dislocations at intersection edges of interfaces are discussed. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216455 Thu, 10 Dec 2009 00:00:00 +0100 3216455 http://www.medworm.com/index.php?rid=3216454&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007623%2Fabstract%3Frss%3Dyes The heat flux during a differential scanning calorimetry (DSC) experiment of a precipitation reaction is expressed analytically as a function of the interfacial energy, the solid solution composition and the precipitate fraction. Using a physically based model of nucleation, growth and dissolution, the respective contributions of these terms are compared for the case of S phase precipitation in AA2024 (Al–4% Cu–2% Mg). Good overall agreement is obtained for the experimental and simulated DSC curves if the interfacial energy is tuned correctly. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216454 Mon, 07 Dec 2009 00:00:00 +0100 3216454 http://www.medworm.com/index.php?rid=3216453&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007611%2Fabstract%3Frss%3Dyes High-strength Ti sheets could be fabricated by effective grain-refinement through high-ratio differential speed rolling for a thickness reduction of 63% in a single rolling pass at room temperature. Formation of narrowly spaced shear bands distributed uniformly over the entire thickness section of the sheet and a high temperature rise by intensive shear banding during rolling resulted in the formation of ultrafine grains with the size of 0.1–0.3μm. The rolled Ti sheet exhibited an ultimate tensile strength of 895–915MPa. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216453 Mon, 07 Dec 2009 00:00:00 +0100 3216453 http://www.medworm.com/index.php?rid=3216452&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007593%2Fabstract%3Frss%3Dyes Homogeneous multilayered barrier films were fabricated by means of reactive and nonreactive sputtering of Al2O3. Homogeneous multilayer structures were seen to possess superior mechanical stability than single-layered films. The multilayer films presented 50% improved barrier performance and the fabrication process was 40% faster compared with single Al2O3 layers of the same thickness. The water vapor transmission rate was enhanced up to the order of 10−4gm−2day−1 from a three-pair system of reactive and nonreactive sputtered Al2O3 bilayers. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216452 Mon, 07 Dec 2009 00:00:00 +0100 3216452 http://www.medworm.com/index.php?rid=3358834&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007532%2Fabstract%3Frss%3Dyes A (ferrite+carbide) microduplex structure formed by dynamic recrystallization of ferrite during warm deformation of martensite was found to exhibit superplastic characteristics. The value of m=0.4 was obtained at 973K and a strain rate of 10−4s−1. Microstructural analysis shows that submicron carbides are located at the ferrite grain boundary, while nanometer ones are dispersed inside ferrite grains. This kind of carbide distribution may suppress the growth of ferrite grains and form a dynamic equilibrium of average grain size during superplastic deformation. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3358834 Fri, 04 Dec 2009 00:00:00 +0100 3358834 http://www.medworm.com/index.php?rid=3166984&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS135964620900757X%2Fabstract%3Frss%3Dyes Changes in the microstructure related to the release of hydrostatic pressure after high-pressure torsion deformation of Cu were studied by freezing the sample before releasing the pressure. Investigations were performed by X-ray line profile analysis using synchrotron radiation. The size of the coherently scattering domains is not strongly affected whereas the dislocation density decreases drastically and the arrangement of the dislocations within the subgrain structure changes to a less stress-intensive one upon pressure release. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3166984 Fri, 04 Dec 2009 00:00:00 +0100 3166984 http://www.medworm.com/index.php?rid=3166983&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007581%2Fabstract%3Frss%3Dyes The formation of a fivefold deformation twin in nanocrystalline Al is studied by the quasicontinuum method. The study focuses on the microstructural effect on the formation process. A particular low-index grain boundary, which has been investigated in a bicrystal model, is observed in the sample. The dislocation reflection and inhomogeneous stress distribution caused by this grain boundary are discussed. The importance of this microstructure to the formation of a fivefold deformation twin is manifested by the results. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3166983 Fri, 04 Dec 2009 00:00:00 +0100 3166983 http://www.medworm.com/index.php?rid=3166982&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007544%2Fabstract%3Frss%3Dyes The effect of temperature on the rolling behavior of an ultrafine-grained Cu with nano-scale twins is reported. Rolling the nano-twinned Cu at liquid nitrogen temperature (LNT) led to a slight drop in hardness with an obvious thickening of twins, while rolling at room temperature (RT) resulted in obvious hardening without change in twin thickness. The strengthening mechanism via dislocation–twin boundary interactions dominates the rolling-induced hardening at RT, and the twinning partial activities are responsible for the de-twinning and softening in rolling at LNT. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3166982 Fri, 04 Dec 2009 00:00:00 +0100 3166982 http://www.medworm.com/index.php?rid=3166981&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007556%2Fabstract%3Frss%3Dyes A two-stage all-solution electrochemical process has been developed to etch a wave-like surface microstructure in titanium. In the first stage, anodization creates a porous oxide surface layer. In the second stage, alcoholic-electrolyte electropolishing removes titanium from beneath the oxide to etch the microstructure. Experimental and simulated angle-resolved reflectivity are compared to confirm that multiple reflections occur inside cavities of the microstructure. The target application is solar cell substrates where multiple reflections can significantly increase the device efficiency. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3166981 Fri, 04 Dec 2009 00:00:00 +0100 3166981 http://www.medworm.com/index.php?rid=3166980&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007568%2Fabstract%3Frss%3Dyes Crack-free interfaces can be achieved in wafer-bonded Ge/Si by using patterned grooves. Using synchrotron radiation phase-contrast imaging and scanning electron microscopy, we observe cracking that is induced by thermal stresses in thin (hGe⩽0.5hSi) Ge wafers on smooth Si substrates. Theoretical calculation shows a remarkable reduction in thermal stresses in Ge wafer bonded to grooved Si substrate. We demonstrate the fabrication of crack-free Ge/Si (hGe=0.5hSi) structure by patterned grooves, as confirmed by an ohmic I–V characteristic across the heterojunction. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3166980 Fri, 04 Dec 2009 00:00:00 +0100 3166980 http://www.medworm.com/index.php?rid=3216451&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007519%2Fabstract%3Frss%3Dyes The boundary structure of deformation twins formed in commercially pure titanium during an initial pass of equal channel angular pressing processing has been studied by transmission electron microscopy (TEM) and high-resolution TEM. A new twinning mode with a twinning dislocation of b3/3 has been identified using a dichromatic diagram method. The new mode of the twin has substantially higher interface energy and accommodates more shear strain during deformation than the conventional b4 twinning mode. The deviation angle between the habit trace of the twin boundary and the theoretical twinning plane, K1, is dependent upon the density of twin dislocations. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216451 Thu, 03 Dec 2009 00:00:00 +0100 3216451 http://www.medworm.com/index.php?rid=3166979&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007507%2Fabstract%3Frss%3Dyes The effect of the distribution of grain orientations on the mechanical behaviour of nanostructured nickel samples obtained by electrodeposition is explored. The dependence of grain size on flow stress is accurately described by the Hall–Petch relationship over a large range of grain sizes (d>20nm). The Hall–Petch slope k depends on orientation texture in relation to the distribution of grain boundaries. The occurrence of two competing physical mechanisms, grain boundary shearing and dislocation emission at grain boundaries, is suggested to explain the experimental data. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3166979 Thu, 03 Dec 2009 00:00:00 +0100 3166979 http://www.medworm.com/index.php?rid=3166978&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007520%2Fabstract%3Frss%3Dyes The size, morphology and configuration of Ni4Ti3 precipitates in a single-crystal Ni–Ti alloy have been investigated by two-dimensional transmission electron microscopy-based image analysis and three-dimensional reconstruction from slice-and-view images obtained in a focused ion beam/scanning electron microscopy (FIB/SEM) dual-beam system. Average distances between the precipitates measured along the compression direction correlate well between both techniques, while particle shape and configuration data is best obtained from FIB/SEM. Precipitates form pockets of B2 of 0.54μm in the compression direction and 1μm perpendicular to the compression direction. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3166978 Thu, 03 Dec 2009 00:00:00 +0100 3166978 http://www.medworm.com/index.php?rid=3216450&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007490%2Fabstract%3Frss%3Dyes Positron annihilation spectroscopy was performed in order to study the influence of preparation route and processing on atomic free volumes in amorphous and nanocrystalline aluminium alloys. In melt-spun amorphous Al88Y7Fe5, structural free volumes smaller than a lattice vacancy are predominant, whereas in amorphous Al92Sm8 prepared by repeated cold rolling larger free volumes occur. In the early stages of nanocrystallization of Al88Y7Fe5, an indication of Y enrichment at interfacial free volumes in the growth front of the Al nanocrystallites is found. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216450 Mon, 30 Nov 2009 00:00:00 +0100 3216450 http://www.medworm.com/index.php?rid=3216449&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007428%2Fabstract%3Frss%3Dyes This paper reports how a multi-stage spark plasma sintering (SPS) schedule can be successfully adopted to consolidate ultrafine-grained ceramics with uniform and better mechanical properties than the widely studied single-stage SPS schedule. To date, a major concern in the materials community is that rapid heating and shorter holding in the single-stage SPS process causes inhomogeneous radial/axial temperature distribution, which is consistent with a number of computational studies. Our new approach to developing better ceramics is expected to address this concern. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3216449 Mon, 30 Nov 2009 00:00:00 +0100 3216449 http://www.medworm.com/index.php?rid=3166977&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007465%2Fabstract%3Frss%3Dyes Electron backscattered diffraction and nanoindentation are used to identify how the local changes of microstructure influence the hardness distributions of cold-sprayed Ni and Cu coatings. The hardness in the vicinity of Ni particle interfaces can be about 1.5GPa higher than that in the particle interior, and this difference is attributed to the cold-spray-induced grain boundaries and dislocation densities. The Cu coating with lower activation energy for recrystallization shows a more uniform microstructure and hardness distribution. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3166977 Mon, 30 Nov 2009 00:00:00 +0100 3166977 http://www.medworm.com/index.php?rid=3166976&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS135964620900743X%2Fabstract%3Frss%3Dyes An automated reconstruction of the pre-transformation microstructure from the microtexture data of the post-transformation product phase is proposed. The method involves identifying triplets of neighboring product grains with a common variant and linking such neighboring triplets via a generalized misorientation criterion. The approach is non-iterative and extremely efficient computationally. The method was tested successfully for different post-transformation microstructures in zirconium. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3166976 Mon, 30 Nov 2009 00:00:00 +0100 3166976 http://www.medworm.com/index.php?rid=3166975&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007477%2Fabstract%3Frss%3Dyes Nucleation of nanograins near crack tips and its role as a special (new) toughening mechanism in deformed nanocrystalline materials are theoretically described. Within our description, stress-driven splitting and migration of grain boundaries occur near crack tips. These stress-driven processes result in nucleation of nanograins and cause a partial stress relaxation near cracks. It is shown that the nucleation of nanograins near crack tips is energetically favorable and effective in enhancing toughness in nanocrystalline ceramic α-Al2O3. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3166975 Mon, 30 Nov 2009 00:00:00 +0100 3166975 http://www.medworm.com/index.php?rid=3166973&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007404%2Fabstract%3Frss%3Dyes We analyze a line defect at the interface between tetradymite-structured Sb2Te3 and rocksalt-structured AgSbTe2 using high-resolution electron microscopy. By determining the step-height and Burgers vector of this defect, we show how motion of the defect, through a diffusive glide mechanism, can transform material from the rocksalt structure to the tetradymite structure. We discuss the atomic flux requirements for this defect motion. This analysis helps to explain the growth mechanism of tetradymite precipitates within rocksalt-structured chalcogenides. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3166973 Mon, 30 Nov 2009 00:00:00 +0100 3166973 http://www.medworm.com/index.php?rid=3120367&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007489%2Fabstract%3Frss%3Dyes Ti/Al multilayered composite, mainly composed of ultrafine equiaxed grains with a mean size of 200–300nm, has been successfully synthesized by accumulative roll bonding (ARB). The microstructure evolution and mechanical properties of the multilayered Ti/Al composite are reported. It was found that large applied shear strain, high strain rate, strain path and the low thermal conductivity of titanium are critical factors for the formation of ultrafine equiaxed grains in Ti/Al multilayered composite during the ARB process. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120367 Mon, 30 Nov 2009 00:00:00 +0100 3120367 http://www.medworm.com/index.php?rid=3120366&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007453%2Fabstract%3Frss%3Dyes A series of Pd–Mg thin films with various thicknesses of Mg were prepared by magnetron sputtering. Their thickness-dependent hydrogen absorption kinetics in the temperature range 298–338K was investigated by modeling the resistance. The hydrogen diffusion in MgH2 films was investigated by electrochemical measurements. We discuss the dominating factor of the absorption kinetics and the critical thickness of the passivating MgH2 layer, as well as the requirements for the advanced hydrogen storage materials under mild conditions. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120366 Mon, 30 Nov 2009 00:00:00 +0100 3120366 http://www.medworm.com/index.php?rid=3120365&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007441%2Fabstract%3Frss%3Dyes We observed large anisotropy of indentation fracture toughness in both mechanically poled and depoled lead titanate zirconate (PZT) ceramics under uniaxial compression up to 400MPa. The fracture toughness anisotropy can reach as much as 3.82 in the former and 3.63 in the latter, which are both considerably larger than that of 2.62 in electrically poled PZT ceramics. This phenomenon is thought to be caused by ferroelastic domain switching during indentation and by the existence of more saturated domain orientation textures under compression than under electrical poling. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120365 Mon, 30 Nov 2009 00:00:00 +0100 3120365 http://www.medworm.com/index.php?rid=3120364&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007416%2Fabstract%3Frss%3Dyes This paper reports an investigation of deformation-induced structural changes of Pd78Cu6Si16 metallic glass observed after the exact positions of the shear bands were identified. The propagation of shear bands induced nanocrystallization not inside the shear bands, but around them. We conclude that the nanocrystal formation results from the accumulating temperature rise caused by the propagation of numerous shear bands. The extremely large temperature rise inside the shear bands may have led to the re-formation of an amorphous structure. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120364 Mon, 30 Nov 2009 00:00:00 +0100 3120364 http://www.medworm.com/index.php?rid=3033529&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007246%2Fabstract%3Frss%3Dyes (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3033529 Fri, 27 Nov 2009 16:30:52 +0100 3033529 http://www.medworm.com/index.php?rid=3166974&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007398%2Fabstract%3Frss%3Dyes The crystal structure of the modulated, low-temperature martensitic phase in Ni2.41Fe0.59Ga ferromagnetic shape memory alloy (FSMA) has been determined by Rietveld refinement of neutron powder diffraction data. The structure shows an incommensurate modulated crystal lattice with some analogies with the 7M modulated martensitic structure found in Ni2Mn1.2Ga0.8 Heusler alloy. The observed type of lattice modulation with q=0.3521c∗ gives rise to a new type of martensitic crystal structure in the FSMAs. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3166974 Fri, 27 Nov 2009 00:00:00 +0100 3166974 http://www.medworm.com/index.php?rid=3166972&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007374%2Fabstract%3Frss%3Dyes The initial stage of secondary recrystallization of Fe–3% Si steel was investigated using a transmission electron microscope with a focus on the existence of sub-boundaries in abnormally growing Goss grains. Ten randomly chosen abnormally growing Goss grains were observed to have sub-boundaries consisting of aligned edge dislocations. In contrast, no sub-boundaries were observed in the matrix grains. The misorientation angles of the observed sub-boundaries were in the range 0.1–0.5°, which was estimated based on the spacing between the dislocations. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3166972 Mon, 23 Nov 2009 00:00:00 +0100 3166972 http://www.medworm.com/index.php?rid=3120363&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007386%2Fabstract%3Frss%3Dyes A unique zinc oxide nanostructure network composed of nanosheets and nanowires was synthesized via a polymer-controlled chemical approach. The field emission and photoresponse properties of the network were investigated. The network exhibited a good field emission property with a low turn-on field of 4.1Vμm−1. Furthermore, this network shows a very low dark current of ∼61pA even at 10V bias which corresponds to 163GΩ resistance, and the ratio between dark and illuminated conditions was more than 1000 at 2V bias. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120363 Mon, 23 Nov 2009 00:00:00 +0100 3120363 http://www.medworm.com/index.php?rid=3120362&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007362%2Fabstract%3Frss%3Dyes Tension–compression asymmetry in Mg–8Al–0.5Zn alloys has been studied as a function of precipitation state. It has been shown that the presence of precipitates significantly reduces yield asymmetry compared with solution treated material. This reduction in asymmetry was attributed to reduced rates of twinning in the presence of Mg17Al12 precipitates. This has been confirmed by texture and microstructure analyses, which show a reduction in the scale and volume fraction of twins in aged and solution treated samples examined at equivalent levels of strain. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120362 Mon, 23 Nov 2009 00:00:00 +0100 3120362 http://www.medworm.com/index.php?rid=3120361&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007350%2Fabstract%3Frss%3Dyes is reported. This alloy undergoes martensitic transformation at 264°C, and has transformation hysteresis of 40.4°C, shape memory effect of 6.2%, compressive plasticity of 22%, and compressive strength of 878MPa. The transformation hysteresis is further expanded by deformation in the martensite state. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120361 Mon, 23 Nov 2009 00:00:00 +0100 3120361 http://www.medworm.com/index.php?rid=3120360&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007349%2Fabstract%3Frss%3Dyes Control of brittleness associated with segregation of sulfur to grain boundaries in ultrafine-grained nickel was investigated. The brittleness could be successfully improved by controlling the grain boundary microstructure. The specimens with a higher fraction of special boundaries can have higher fracture toughness even in sulfur-bearing condition. It is evident that grain boundary engineering is applicable to controlling segregation-induced embrittlement in ultrafine-grained materials. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120360 Mon, 23 Nov 2009 00:00:00 +0100 3120360 http://www.medworm.com/index.php?rid=3120359&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007337%2Fabstract%3Frss%3Dyes As-delivered austenitic stainless steel and nitrogen stabilized expanded austenite, both fully nitrided and denitrided (in H2), were investigated with Cr, Fe and Ni extended X-ray absorption fine structure. The data shows pronounced short-range ordering of Cr and N. For the denitrided specimen the N atoms remaining in the solid state after H2-reduction are trapped by Cr atoms. Quantitative interpretation in terms of the local distortions around Cr atoms and their N coordination number reveals that no Cr–N clusters or CrN platelets are present. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120359 Thu, 19 Nov 2009 00:00:00 +0100 3120359 http://www.medworm.com/index.php?rid=3120358&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007325%2Fabstract%3Frss%3Dyes In the present study, the yield strength of a maraging steel was modeled using data gained by atom probe tomography. The influence of reverted austenite on the strength was considered as tensile tests on samples consisting of pure austenite were performed and subtracted from the overall curves. Furthermore, a new approach which considers the distribution of the particles sizes was used to describe the age-hardening phenomena. This leads to significantly improved agreement with the experimental data. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120358 Thu, 19 Nov 2009 00:00:00 +0100 3120358 http://www.medworm.com/index.php?rid=3120357&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007313%2Fabstract%3Frss%3Dyes The hexacelsian-to-celsian phase transformation in Ba1–xSrxAl2Si2O8 is of interest for environmental barrier coating applications. Plasma-sprayed microstructures were heat treated above 1100°C and the kinetics of the hexacelsian-to-celsian transformation were quantified. Activation energies for bulk and crushed materials were determined to be ∼340 and ∼500kJmol−1, respectively. X-ray diffraction and electron backscattered diffraction were used to establish how plasma spraying barium- and strontium-doped aluminosilicate effectively reduces the energy required for its transformation. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120357 Thu, 19 Nov 2009 00:00:00 +0100 3120357 http://www.medworm.com/index.php?rid=3120356&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007301%2Fabstract%3Frss%3Dyes Ta-particulate reinforced Zr–Ni–Cu–Al–Ta bulk metallic glass matrix composite exhibits good mechanical properties of ∼23% plasticity in compression and 1.8% plasticity in tension without any sacrifice of strength. In situ SEM observations of tension tests combined with finite element simulation reveals that plastic deformation of Ta particles creates shear stress concentration on the interface and tunes shear stress distribution, which initiates and arrests shear bands, leading to the formation of multiple shear bands. This contributes to the enhanced plasticity of the present composite. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120356 Thu, 19 Nov 2009 00:00:00 +0100 3120356 http://www.medworm.com/index.php?rid=3294481&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007167%2Fabstract%3Frss%3Dyes In this research, template-guided self-ordering of wrinkled ZnO microstructures on sol–gel-derived ZnO films has been fabricated with poly(methyl methacrylate) (PMMA) templates. The orientation of the ZnO wrinkles was perpendicular to the PMMA trenches due to the presence of resultant solvent diffusion force along the trenches. The difference between the thermal expansion coefficients of the thin film and the templates may also play an important role in dominating the integrity of the ordered wrinkles grown in the confined trenches. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3294481 Mon, 16 Nov 2009 00:00:00 +0100 3294481 http://www.medworm.com/index.php?rid=3166971&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007179%2Fabstract%3Frss%3Dyes As-received ultrahigh 300M strength steel was impacted at strain rates of 1×103 and 4×103s–1. At the strain rate of 1×103s–1, the retained austenite transformed into upper bainite and M7C3 precipitates. Fine Mo2C carbides precipitated in the bainitic ferrite matrix in addition to upper bainite during deformation contribute to the strengthening effect at a relatively high strain rate of 4×103s–1. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3166971 Mon, 16 Nov 2009 00:00:00 +0100 3166971 http://www.medworm.com/index.php?rid=3120355&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007192%2Fabstract%3Frss%3Dyes It is known that decreasing the hydrogenation temperature results in a loss of hydrogen capacity of Mg powders. Based on the model that hydrogen capacity is reached when hydride colonies/crystals formed on the surface of particles impinge on each other and form a continuous layer, it is elucidated, through a two-step hydrogenation experiment and detailed microstructural analysis, that the reduced hydrogen capacity at low temperatures is associated with an increase in the hydride nucleation rate. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120355 Mon, 16 Nov 2009 00:00:00 +0100 3120355 http://www.medworm.com/index.php?rid=3120354&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007180%2Fabstract%3Frss%3Dyes The dislocation microstructure of strontium titanate plastically deformed below room temperature shows dipolar configurations of a〈110〉 screw dislocations. The dipole height is so small that dipole annihilation is expected. Here we show why this is inhibited. By high-resolution transmission electron microscopy observations we find that in such dipoles each dislocation is dissociated into two collinear a/2〈110〉 partials on a {110} plane. Elasticity theory calculations provide a stacking-fault energy value of 340±90mJm−2. Finally, we discuss the effects of this dissociation process on the mechanical behaviour. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120354 Mon, 16 Nov 2009 00:00:00 +0100 3120354 http://www.medworm.com/index.php?rid=3120351&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007131%2Fabstract%3Frss%3Dyes Inkjet printed patterns using copper nanoparticles (NPs) were sintered at 250°C under reducing atmosphere. The size of NPs covered by organic capping molecules was 5nm on average. A crack-free Cu film was obtained after sintering. The grain size of the film reached 500nm upon grain growth. However, only agglomeration of NPs was observed at the bottom of the film. The resistance was 0.88Ω on average and the patterns were electrically tested by light-emitting diodes. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120351 Mon, 16 Nov 2009 00:00:00 +0100 3120351 http://www.medworm.com/index.php?rid=2989027&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209006836%2Fabstract%3Frss%3Dyes (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=2989027 Fri, 13 Nov 2009 16:35:00 +0100 2989027 http://www.medworm.com/index.php?rid=2989026&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209006988%2Fabstract%3Frss%3Dyes (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=2989026 Fri, 13 Nov 2009 16:34:59 +0100 2989026 http://www.medworm.com/index.php?rid=3120353&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007155%2Fabstract%3Frss%3Dyes By means of X-ray photoelectron spectrometry depth profile and transmission electron microscopy analysis, this study reveals that amorphous Cu54Ni6Zr22Ti18 powders are enveloped by a thick (∼30nm) oxide skin and a subsequent oxidation-induced partially nanocrystallized zone. The thick oxide skin changes the metallic glass surface to oxide ceramic. It is proposed that effective disruption of the oxide skin is essential to the sintering of metallic glass. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120353 Fri, 13 Nov 2009 00:00:00 +0100 3120353 http://www.medworm.com/index.php?rid=3120352&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007143%2Fabstract%3Frss%3Dyes A method is presented for the simultaneous measurement of relative grain boundary energy and all five macroscopic grain boundary degrees of freedom in leaded copper. When compared to the Wynblatt–Takashima model, results suggest a lowered boundary energy when there are equal broken-bond densities on either side of the boundary. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120352 Fri, 13 Nov 2009 00:00:00 +0100 3120352 http://www.medworm.com/index.php?rid=3120350&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS135964620900712X%2Fabstract%3Frss%3Dyes Variations in the Poisson’s ratios (ν) of a variety of metallic glasses and non-metallic glasses were investigated under high pressure and low temperature (270–100K). It was found that there are direct correlations between Poisson’s ratio and its differential upon pressure or temperature. These correlations suggest a way to understand the microstructure of and plastic deformation in metallic glasses. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120350 Fri, 13 Nov 2009 00:00:00 +0100 3120350 http://www.medworm.com/index.php?rid=3120349&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007118%2Fabstract%3Frss%3Dyes The majority of aero-structural titanium alloys are high-speed milled. This paper identifies microstructural subsurface damage in the form of intense slip bands after high-speed milling of Ti–6Al–4V and Ti-834. Such microstructural features are undetected by current surface integrity techniques. The alignment and density of the intense slip bands were found to be dependent on the subsurface alpha grain orientation. Such microstructural subsurface damage could degrade in-service properties, due to a reduction in fatigue crack initiation resistance. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120349 Fri, 13 Nov 2009 00:00:00 +0100 3120349 http://www.medworm.com/index.php?rid=3166970&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007088%2Fabstract%3Frss%3Dyes A large temperature range of stress-induced martensitic transformation with >8% superelastic strain is demonstrated in [100]-oriented Co49Ni21Ga30 single crystals. The nature of the superelastic response is greatly affected by temperature and test history due to the temperature-dependent dominant microstructural mechanisms. We provide an insight into these mechanisms and divide the response into three temperature stages. Interestingly, a small stress hysteresis of only 2MPa was achieved after the superelastic experiments at 300°C compared to 20MPa of the virgin sample. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3166970 Thu, 12 Nov 2009 00:00:00 +0100 3166970 http://www.medworm.com/index.php?rid=3120347&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS135964620900709X%2Fabstract%3Frss%3Dyes In situ electrochemical hydrogen charging in combination with atomic force microscopy and optical microscopy has been used to study the effect of hydrogen on the austenite phase in super duplex stainless steel. Observations showed that hydrogen charging results in an irreversible deformation of austenite. High residual tensile stresses form in austenite during quench annealing. These stresses, in combination with the activation of dislocation sources by hydrogen, result in formation of slip lines on the austenite surface during in situ hydrogen charging. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120347 Thu, 12 Nov 2009 00:00:00 +0100 3120347 http://www.medworm.com/index.php?rid=3120348&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007106%2Fabstract%3Frss%3Dyes The plastic deformation behavior of twinning-induced plasticity steels of composition Fe–25Mn–3Si–3Al are investigated by means of in situ synchrotron high-energy X-ray diffraction and compared to self-consistent simulations. It is the first time the alternating interaction of {111} slip and {111} twinning have been directly observed in situ while undergoing uniaxial tension. The deformation texture is determined mainly by dislocation gliding, while deformation twinning impedes the reinforcement of texture. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120348 Wed, 11 Nov 2009 00:00:00 +0100 3120348 http://www.medworm.com/index.php?rid=3120346&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007076%2Fabstract%3Frss%3Dyes Investigation of crystal structure and multiferroic properties of polycrystalline Bi1–xSmxFeO3 (0.1⩽x⩽0.2) samples was performed by X-ray diffraction, piezoresponse force microscopy and SQUID-magnetometry techniques. It was shown that increasing samarium content induced a polar-to-nonpolar phase transition near x=0.2. Within the polar region, a rhombohedral and two orthorhombic modifications of Bi1–xSmxFeO3 were found. It was shown that samarium substitution resulted in the appearance of spontaneous magnetization, which was significantly enhanced upon the composition-driven transition from a rhombohedral to an orthorhombic phase. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120346 Mon, 09 Nov 2009 00:00:00 +0100 3120346 http://www.medworm.com/index.php?rid=3120345&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007064%2Fabstract%3Frss%3Dyes To study the change of modulation direction during deformation, two NiMnGa single crystals, one with a five-layered modulated tetragonal structure (5M) and the other with a seven-layered modulated orthorhombic structure (7M), were chosen. Synchrotron diffraction experiments show that the modulation takes place on the {110) plane along the 〈110] directions. During deformation the c-axis orientation changes by twinning, and with this the direction of modulation obeying the twin relation also changes. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120345 Mon, 09 Nov 2009 00:00:00 +0100 3120345 http://www.medworm.com/index.php?rid=3120344&cid=s_38431_173_f&fid=38431&url=http%3A%2F%2Fwww.scriptamat.org%2Farticle%2FPIIS1359646209007052%2Fabstract%3Frss%3Dyes This work explores the suggestion that the temperature dependence of the grain boundary free energy can be estimated from the temperature dependence of the elastic constants. The temperature-dependent elastic constants and free energy of a symmetric Σ79 tilt boundary are computed for an embedded atom method model of Ni. The grain boundary free energy scales with the product of the shear modulus times the lattice constant for temperatures up to about 0.75 the melting temperature. (Source: Scripta Materialia) Scripta Materialia journals http://www.medworm.com/rss/comments.php?id=3120344 Mon, 09 Nov 2009 00:00:00 +0100 3120344