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Showing papers in "Acta Materialia in 2004"


Journal ArticleDOI
TL;DR: The influence of the grain size on the flow stress of extruded Mg-3Al-1Zn tested in compression is examined in this paper, where samples with grain sizes varying between 3 and 23 μm were prepared by altering the extrusion conditions.

1,160 citations


Journal ArticleDOI
TL;DR: In this article, the authors demonstrate three strategies to achieve relatively large stable tensile deformation in nanostructured metals, using the pure Cu processed by equal channel angular pressing as a model.

860 citations


Journal ArticleDOI
TL;DR: In this paper, the microstructures and mechanical properties of equal-channel angular pressing (ECAP) processed and naturally aged ultrafine grained (UFG) and coarse-grained (CG) 7075 Al alloys as well as their evolutions during annealing were investigated.

787 citations


Journal ArticleDOI
TL;DR: In this paper, the formation of metastable platelets in early-stage precipitation of a 7050 Al alloy aged at 121 °C was investigated using transmission electron microscopy, together with 3-dimensional atom probe analysis.

597 citations


Journal ArticleDOI
TL;DR: In this article, the fundamental concepts of grain boundary engineering (GBE) accompanied by a critical appraisal of GBE investigations are reported, and several variants on processing route schedules to produce successfully a GBE microstructure with improved properties.

559 citations


Journal ArticleDOI
TL;DR: The compositional dependence of a glass-forming ability was systematically studied in a binary alloy series Cu100−xZrx (x=34, 36, 38.2, 40 at%) by the copper mold casting method.

548 citations


Journal ArticleDOI
TL;DR: In this article, the influence of the microstructure and the misorientation relationship between grains on the mechanical properties is investigated in specimens of ultrafine-grained copper processed by equal channel angular extrusion (ECAE) route B C in 1, 2, 4, 8, 12 and 16 passes.

528 citations


Journal ArticleDOI
TL;DR: In this article, it was shown that the density of the nuclei is a function of the HPT strain and determined together with the annealing temperature the grain size of the nanocrystals ranging from 5 to 350 nm.

474 citations


Journal ArticleDOI
TL;DR: In this article, a third generation Ni-base single-crystal superalloy TMS-75 and its γ/γ " tie line alloys were designed to contain various volume fractions of γ, while the compositions of two individual phases were kept the same.

444 citations


Journal ArticleDOI
TL;DR: In this paper, a highly ordered array of parallel multi-wall CNTs in an alumina matrix was fabricated and the damage was examined by scanning electron microscopy, and the quantitative indentation data and computational models were used to determine the multiwall axial Young's modulus as 200-570 GPa, depending on the nanotube geometry and quality.

442 citations


Journal ArticleDOI
TL;DR: In this article, the thermodynamic properties of Al, Ni, NiAl, and Ni3Al were studied using the first-principles approach using the ab initio plane wave pseudopotential method within the generalized gradient approximation.

Journal ArticleDOI
TL;DR: In this article, high-strength Fe-based bulk glassy alloys with super-high fracture strength of over 4000 MPa and high glass-forming ability were synthesized by the copper mold casting method.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the character of plastic deformation in metallic glasses through instrumented nanoindentation experiments on amorphous Pd40Ni40P20 and Mg65Cu25Gd10.

Journal ArticleDOI
TL;DR: In this paper, the evolution of microstructure and texture of a TWIP-steel during cold rolling was studied, and the presence of deformation twinning at low strains ( e 〈1 1 2〉 is dominant at every strain level.

Journal ArticleDOI
TL;DR: In this article, the temperature dependence of dielectric permittivity of BZT ceramics has been investigated and it is shown that the phase transition temperature TC (or Tm) is suppressed with increasing Zr content.

Journal ArticleDOI
TL;DR: In this paper, a nanostructured surface layer up to 50 μm thick was produced on commercially pure titanium using surface mechanical attrition treatment (SMAT), and the microstructural features of the surface layer produced by SMAT were systematically characterized by cross-sectional optical microscopy observations, transmission electron microscopy (TEM) and high-resolution transmission electron microscope (HRTEM) investigations.

Journal ArticleDOI
TL;DR: In this article, a new embedded-atom potential has been developed for Ni3Al by fitting to experimental and first-principles data, which describes lattice properties of Ni 3Al, point defects, planar faults, as well as the γ and γ′ fields on the Ni-Al phase diagram.

Journal ArticleDOI
TL;DR: In this article, the authors postulate that almost any motion of an interface between two crystals can produce a coupled tangential motion of the two crystals relative to each other which is proportional to the normal motion.

Journal ArticleDOI
TL;DR: In this article, differently heat treated samples of a low alloyed TRIP steel have been investigated using electron diffraction techniques in SEM and TEM, and the results showed that the mechanical properties of these samples are most strongly influenced by the amount and distribution of carbon in the retained austenite and by the degree of recovery in bainite and martensite.

Journal ArticleDOI
TL;DR: In this paper, the elastic and plastic properties of carbon nanotubes (CNTs) under axial tension were examined using the molecular dynamics simulation performed in the microcanonical ensemble.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the temperature dependencies of true strain-hardening and plastic-instability properties for austenitic stainless steels; including annealed 304, 316, 316LN, and 20% cold-worked 316LNs, at test temperatures from −150 to 450 °C.

Journal ArticleDOI
TL;DR: In this article, in situ nanoindentation within a transmission electron microscope was used to investigate the deformation mechanisms in ultrafine-grained Al films and the results suggest that grain growth and coalescence are important modes of response in deformation of ultrafine and nanograined materials.

Journal ArticleDOI
TL;DR: In this article, a model based on free-growth control of grain initiation is proposed to quantitatively predict the grain size in aluminium alloys inoculated with commercial refiner as a function of refiner addition level, solute content in the melt and cooling rate.

Journal ArticleDOI
TL;DR: In this paper, an extensive, systematic first-principles study of the thermodynamics of all the reported precipitate phases of Mg-Si-Cu alloys was performed using density functional-based calculations in both the local density and generalized gradient approximations.

Journal ArticleDOI
TL;DR: In this paper, a criterion for the emission of a dislocation from the surface of a void under remote tension is formulated, analogous to Rice and Thomsons criterion for crack blunting by dislocation emission from the crack tip.

Journal ArticleDOI
TL;DR: In this article, a model based on inelastic column theory incorporating strain hardening was able to predict the lattice truss core's compressive peak strength capacity in both the annealed and age hardened conditions, for all relative densities tested.

Journal ArticleDOI
TL;DR: In this article, a micro-mechanical model based on reversible thermodynamics was modified to account for plastic relaxation of coherent transforming interfaces, and the predictions account for the growing hysteresis with increasing external stress.

Journal ArticleDOI
TL;DR: In this paper, a phase-field model based on the time-dependent Ginzburg-Landau equation was used to simulate the polarization switching in a ferroelectric subjected to an electric field or a stress field.

Journal ArticleDOI
TL;DR: In this paper, the authors used nanoindentation to extract the elastic and plastic properties of Cu, Sn-3.5Ag solder, Ag3Sn, Cu6Sn5, and Cu3Sn.

Journal ArticleDOI
TL;DR: In this paper, a new methodology to extract the plastic properties of metallic materials from an instrumented spherical indentation loading curve has been proposed using dimensional analysis and finite element computations.