Multiscale modeling of plastic deformation of molybdenum and tungsten: I. Atomistic studies of the core structure and glide of 1/2〈1 1 1〉 screw dislocations at 0 K

By R. Gröger, A. Bailey, V. Vítek. 2008

275 citations recorded by the source corpus.

Abstract Owing to their non-planar cores, 1/2〈1 1 1〉 screw dislocations govern the plastic deformation of body-centered cubic (bcc) metals. Atomistic studies of the glide of these dislocations at 0 K have been performed using Bond Order Potentials for molybdenum and tungsten that account for the mixed metallic and covalent bonding in transition metals. When applying pure shear stress in the slip direction significant twinning–antitwinning asymmetry is displayed for molybdenum but not for tungsten. However, for tensile/compressive loading the Schmid law breaks down in both metals, principally due to the effect of shear stresses perpendicular to the slip direction that alter the dislocation core. Recognition of this phenomenon forms a basis for the development of physically based yield criteria that capture the breakdown of the Schmid law in bcc metals. Moreover, dislocation glide may be preferred on {1 1 0} planes other than the most highly stressed one, which is reminiscent of the anomalous slip observed in many bcc metals.

Subfields: Atomic and Molecular Physics, and Optics, Biomedical Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/7c8c0b9a5222ebd1e3e7e33665bdcbcd7f1e62b6

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Citations in the corpus

Spectral neighbor analysis method for automated generation of quantum-accurate interatomic potentials (2014, methodology): “um, the screw dislocations are known to play a crucial role. The structure and motion of screw dislocations in BCC metals has been examined for many years and is discussed in detail by Groger et al. [26] and by references therein. A crucial feature of screw dislocations in BCC metals is the Peierls ”
Unraveling the temperature dependence of the yield strength in single-crystal tungsten using atomistically-informed crystal plasticity calculations (2015, methodology): “…noting that the relation between tcc and s has been established for tensile nonglide stresses only (s > 0), for consistency with the linear dependence used in the work of Vitek and collaborators (Gr€oger et al., 2008a,b) that has been used in other crystal plasticity works (Koester et al., 2012).”