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Title: Structure of screw dislocation core in Ta at high pressure

The core structure and Peierls stress of the 1/2 〈111〉(110) screw dislocation in Ta have been investigated theoretically using the modified Peierls–Nabarro theory that takes into account the discreteness effect of crystal. The lattice constants, the elastic properties, and the generalized-stacking-fault energy(γ-surface) under the different pressures have been calculated from the electron density functional theory. The core structure of dislocation is determined by the modified Peierls equation, and the Peierls stress is evaluated from the dislocation energy that varies periodically as dislocation moves. The results show the core width and Peierls stress in Ta are weakly dependent of the pressure up to 100 GPa when the length and stress are measured separately by the Burgers vector b and shear modulus μ. This indicates that core structure is approximately scaling invariant for the screw dislocation in Ta. The scaled plasticity of Ta changes little in high pressure environment.
Authors:
; ; ;  [1]
  1. Institute for Structure and Function and Department of Physics, Chongqing University, Chongqing 400030 (China)
Publication Date:
OSTI Identifier:
22277947
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 9; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; APPROXIMATIONS; CRYSTALS; ELASTICITY; ELECTRON DENSITY; LATTICE PARAMETERS; PERIODICITY; PLASTICITY; PRESSURE DEPENDENCE; SCREW DISLOCATIONS; SHEAR PROPERTIES; STACKING FAULTS; STRESSES; SURFACES; TANTALUM