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Showing papers in "Acta Materialia in 2009"


Journal ArticleDOI
TL;DR: The absolute grain boundary mobility of 388 nickel grain boundaries was calculated using a synthetic driving force molecular dynamics method; complete results appear in the Supplementary materials as discussed by the authors. But the authors did not consider the effect of boundary mobility on grain boundary roughening.

646 citations


Journal ArticleDOI
TL;DR: In this article, the influence of large (>1μm diameter) particles on the recrystallization behavior of magnesium alloys deformed in plane strain compression has been studied.

623 citations


Journal ArticleDOI
TL;DR: In this paper, the authors review the most important findings in this technologically important area that impact Our quantitative understanding of: (i) key anisotropic properties of the solid liquid interface that govern solidification pattern evolution, including the solid-liquid interface free energy and the kinetic coefficient; (ii) dendritic solidification at small and large growth rates.

612 citations


Journal ArticleDOI
TL;DR: In this paper, a two-step annealing process has been used to produce samples with large variations in structural parameters such as boundary spacing, misorientation angle and dislocation density.

492 citations


Journal ArticleDOI
TL;DR: In this article, the double-differentiation method was used to define the critical strain for initiation of DRX and the net softening attributable to DRX was then defined as the difference between the σrecov and experimental curves.

480 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated the relationship between the processing parameters, the heat and plastic deformation produced and the resulting microstructure and mechanical properties in friction stir welding (FSW).

415 citations


Journal ArticleDOI
TL;DR: In this paper, the structural and compositional changes at the nanometer scale associated with the nucleation and growth of α precipitates in the β titanium alloy Ti-5553 with ω precipitates acting as heterogeneous nucleation sites are discussed.

411 citations


Journal ArticleDOI
TL;DR: In this article, design rules are proposed by which the compositions of nickel-based single crystal superalloys can be chosen systematically, using models for the most important characteristics: creep resistance, microstructural stability, castability, density and cost.

407 citations


Journal ArticleDOI
TL;DR: In this article, a state-of-the-art ZT of 1.0 has been achieved for the levitation-melted and spark-plasma-sintered half-Heusler thermoelectric alloys.

371 citations


Journal ArticleDOI
TL;DR: In this paper, an extensive experimental study characterizing the sequence of events that lead to the formation of a very high density of Y-Ti-O solute nanoclusters (NC) in mechanically alloyed, hot isostatically pressed ferritic stainless steels is reported.

363 citations


Journal ArticleDOI
TL;DR: In this article, the feasibility of using grain-boundary engineering techniques to reduce the susceptibility of a metallic material to intergranular embrittlement in the presence of hydrogen is examined.

Journal ArticleDOI
TL;DR: In this article, the breakdown of full icosahedral clusters is identified as a structural signature of the initiation of shear localization, which is demonstrated to be a spontaneous and autocatalytic instability propagating with a velocity close to the speed of sound.

Journal ArticleDOI
TL;DR: In this article, two twinning mechanisms for hexagonal-close-packed crystals at an atomic scale were studied using topological analysis and atomistic simulations, and the results show that the zonal-twinning mechanism is energetically favorable relative to the normal-twin mechanism, because the Zn dislocation has a smaller Burgers vector.

Journal ArticleDOI
TL;DR: In this article, equal-channel angular pressing (ECAP) was used to investigate the influence of stacking fault energy (SFE) on the microstructural evolution during deformation and corresponding mechanical properties.

Journal ArticleDOI
TL;DR: In this article, the authors studied the link between the indentation size effect and the density of geometrically necessary dislocations (GNDs) through the following approach: four indents of different depth and hardness were placed in a Cu single crystal using a conical indenter with a spherical tip.

Journal ArticleDOI
TL;DR: In this article, the authors demonstrate why and how these elastic and plastic properties are correlated, in terms of the common structural origin underlying these mechanical behaviors in MGs, and identify the full icosahedral ordering as the key structural feature in the Cu-Zr MGs that controls not only the G and the G/B, but also the initiation of shear localization and the intrinsic plasticity.

Journal ArticleDOI
TL;DR: In this paper, the microstructure during cold rolling and annealing of a low-stacking fault energy austenitic Fe-Mn-C alloy was studied by means of electron microscopy.

Journal ArticleDOI
TL;DR: In this paper, the concept of hierarchical design is applied to conventional compounds such as alumina and poly(methyl methacrylate) (PMMA) to make bulk hybrid materials that display exceptional toughness that can be nearly 300 times higher than either of their constituents.

Journal ArticleDOI
TL;DR: In this article, the authors present a pragmatic engineering model to study aspects of the SLM process using an enthalpy formulation and accounting for shrinkage and laser light penetration, and investigate the importance of evaporation for a set of process parameters relevant to production.

Journal ArticleDOI
TL;DR: In this paper, the authors explore the bonding features and mechanisms present in kinetic spray coatings of commercially pure titanium (CP-Ti) by linking experimental observations with finite element modeling for the purpose of optimizing the deposition process.

Journal ArticleDOI
TL;DR: In this article, single-crystal micro-cantilever beams were manufactured from a polycrystalline commercially pure Ti sample using a focused ion beam and a nano-indenter was then used to conduct micro-bending tests.

Journal ArticleDOI
TL;DR: In this paper, the authors present a new theory for the size of the hysteresis based on the growth from a small scale of fully developed austenite martensite needles.

Journal ArticleDOI
TL;DR: In this paper, the fatigue behavior of polycrystalline nickel-based superalloy Rene 88DT was examined in the lifetime regime of 105-109 cycles at 593-°C in air using an ultrasonic fatigue apparatus operating at frequencies close to 20 kHz.

Journal ArticleDOI
TL;DR: In this article, the mechanism of the increase in coercivity caused by post-sinter annealing of Nd-Fe-B-based magnets was investigated by high-resolution scanning electron microscopy, transmission electron microscope and atom probe tomography.

Journal ArticleDOI
TL;DR: In this paper, an in-depth statistical analysis using electron backscatter diffraction (EBSD) is carried out to expose statistical correlations between { 10 1 ¯ 2 } twinning and grain size, crystallographic orientation, grain boundary length, and neighbor misorientation in high-purity polycrystalline zirconium strained to 5% and 10% at 77 K.

Journal ArticleDOI
TL;DR: In this article, it was shown by transmission electron microscopy that equal-channel angular pressing (ECAP) affects the morphology of precipitates in an Al-Zn-Mg-Cu alloy.

Journal ArticleDOI
TL;DR: In this paper, post-mortem scanning transmission electron microscopy reveals no apparent retained martensite but rather a macroscopic band of dislocation activity within which are planar arrays of ∼100nm dislocation loops involving a single slip system.

Journal ArticleDOI
TL;DR: In this article, the evolution of the microstructure of a 12% Cr tempered martensite ferritic steel under conditions of long-term aging and creep (823 K, 120 MPa, t R ǫ =139, 971 H) was investigated, showing how subgrains coarsen, that the close correlation between carbides and subgrain boundaries loosens during longterm creep and that the frequency of smallangle boundaries increases.

Journal ArticleDOI
TL;DR: In this article, the fracture characteristics of the reinforcing particles were rationalized using a proposed fracture criterion, and the yield strength and the elastoplastic deformation of such composites containing a high volume fraction of glassy particles were accurately modeled using a shear lag model and a self-consistent effective medium approach.

Journal ArticleDOI
TL;DR: Based on microstructural investigations, a solidification mechanism is proposed for these bulk metallic glass (BMG) composites in this article, which enhances the compressive plasticity (plastic strain up to 14%) and both plastic strain as well as yield strength scale with the crystalline volume fraction.