Anharmonic effect on the thermally activated migration of {101̄2} twin interfaces in magnesium

Sato, Yuji; Swinburne, Thomas D.; Ogata, Shigenobu; Rodney, David

doi:10.1080/21663831.2021.1875079

Cited by 17 publications

(5 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Section 4.1) but also at high temperatures. Moreover, anharmonicity may become important at high temperatures, requiring to use more precise approaches relying on thermodynamic integration [79,82,83]. These approaches are still too computationally expensive for ab initio calculations, particularly in the case of a kinked dislocation.…”

Section: Dislocation Velocity and Yield Stressmentioning

confidence: 99%

Screw dislocations in BCC transition metals: from ab initio modeling to yield criterion

Clouet¹,

Bienvenu²,

Dézerald³

et al. 2021

Comptes Rendus. Physique

Self Cite

View full text Add to dashboard Cite

We show here how density functional theory calculations can be used to predict the temperatureand orientation-dependence of the yield stress of body-centered cubic (BCC) metals in the thermallyactivated regime where plasticity is governed by the glide of screw dislocations with a 1/2〈111〉 Burgers vector. Our numerical model incorporates non-Schmid effects, both the twinning/antitwinning asymmetry and non-glide effects, characterized through ab initio calculations on straight dislocations. The model uses the stress-dependence of the kink-pair nucleation enthalpy predicted by a line tension model also fully parameterized on ab initio calculations. The methodology is illustrated here on BCC tungsten but is applicable to all BCC metals. Comparison with experimental data allows to highlight both the successes and remaining limitations of our modeling approach.

show abstract

Section: Dislocation Velocity and Yield Stressmentioning

confidence: 99%

Screw dislocations in BCC transition metals: from ab initio modeling to yield criterion

Clouet¹,

Bienvenu²,

Dézerald³

et al. 2021

Comptes Rendus. Physique

Self Cite

View full text Add to dashboard Cite

show abstract

“…When viewed as threedimensional domains, these disconnections are "terraces," which nucleate, grow laterally, and coalesce to advance the twin boundary (25,26). Sato et al (29) and Spearot et al (25,26) also suggested that the disconnection nucleation and migration rates can be affected by a variety of parameters, such as shear stress, temperature, orienta tion, and structure. This predicted glide mechanism (assisted by a local shuffling) has been supported by several highresolution TEM (HRTEM) observations of coherent twin boundaries (CTBs) decorated with disconnections (17)(18)(19).…”

Section: Introductionmentioning

confidence: 99%

Twin boundary migration mechanisms in quasi-statically compressed and plate-impacted Mg single crystals

et al. 2021

View full text Add to dashboard Cite

Twinning is a prominent deformation mode that accommodates plasticity in many materials. This study elucidates the role of deformation rate on the atomic-scale mechanisms that govern twin boundary migration. Examination of Mg single crystals deformed under quasi-static compression was compared with crystals deformed via plate impact. Evidence of two mechanisms was uncovered. Atomic-level observations using high-resolution transmission electron microscopy revealed that twin boundaries in the -axis quasi-statically compressed single crystals are relatively smooth. At these modest stresses and rates, the twin boundaries were found to migrate predominantly via shear (i.e., disconnection nucleation and propagation). By contrast, in the plate-impacted crystals, which are subjected to higher stresses and rates, twin boundary migration was facilitated by local atomic shuffling and rearrangement, resulting in rumpled twin boundaries. This rate dependency also leads to marked variations in twin variant, size, and number density in Mg. Analogous effects are anticipated in other hexagonal closedpacked crystals.

show abstract

“…In the context of plasticity, the present random stress environment can be generated and implemented in a dislocation dynamics framework [57,58] to study for instance the competition between solid-solution and precipitation hardening in complex alloys. Beyond dislocations, any stress-induced microstructural process, such as the migration of twin interfaces [59] and other grain boundaries, could also be modeled in random alloys, accounting for the strong anisotropy of the correlations evidenced in the present study. Finally, using the expression of the mean-square displacement u 2 given in Ref.…”

Section: Discussionmentioning

confidence: 99%

Microelasticity model of random alloys. Part II: displacement and stress correlations

Geslin

Rida

Rodney

2021

Journal of the Mechanics and Physics of Solids

Self Cite

View full text Add to dashboard Cite

In this two-part article, we propose elastic models of disordered alloys to study the statistical properties of the random displacement and stress fields emerging from the random distributions of atoms of different sizes. In Part I, we presented realand Fourier-space approaches enabling to obtain the amplitude of the fluctuations through the mean square displacements and stresses. In the present Part II, we extend the Fourier approach to address spatial correlations. We show that, even if the alloy is fully disordered and elastically isotropic, correlations are highly anisotropic. Our continuum predictions are validated by comparisons with atomistic models of random alloys. We also discuss the consequence of displacement correlations on finite size effects in atomistic calculations and on diffuse X-ray and neutron scattering experiments and the possible implications of stress correlations on dislocation behavior.Random alloys are solid solutions of two or more components where atoms of different nature are located randomly on the crystalline lattice. The plasticity of random alloys has been of significant interest for several decades [1, 2, 3] but has recently attracted a renewed attention with the development of high entropy alloys (HEA) [4,5,6]. The size difference between the alloy components induces displacements of the atoms from their lattice sites, as well as internal stresses. These atomic displacements, also referred to as "lattice distortion" in the literature [5,6] have been the focus of multiple studies because they were found to correlate well with solid solution strengthening and can be assessed by both experimental (using X-ray [5

show abstract

Anharmonic effect on the thermally activated migration of {101̄2} twin interfaces in magnesium

Cited by 17 publications

References 41 publications

Screw dislocations in BCC transition metals: from ab initio modeling to yield criterion

Screw dislocations in BCC transition metals: from ab initio modeling to yield criterion

Twin boundary migration mechanisms in quasi-statically compressed and plate-impacted Mg single crystals

Microelasticity model of random alloys. Part II: displacement and stress correlations

Contact Info

Product

Resources

About