2008/07/16 by Roman Gröger, Gröger, R., Aimee Gotway Bailey +3 · 2 citations
Engineering · Materials Science · #Advanced Materials Characterization Techniques #FOS: Physical sciences #Material Properties and Failure Mechanisms #Materials Science (cond-mat.mtrl-sci) #Microstructure and mechanical properties
paper · pdf · doi:10.48550/arxiv.0807.2667
openalex publication_date 2008/07/16 · openalex created_date 2024/04/11 · openalex updated_date 2026/07/28
Owing to their non-planar cores 1/2<111> screw dislocations govern the plastic deformation of 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 it displays significant twinning-antitwinning asymmetry 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 110 planes other than the most highly stressed one, which is reminiscent of the anomalous slip observed in many BCC metals.