Hydrogen-Induced Core Structures Change of Screw and Edge Dislocations in Tungsten

Abstract

A Quantum Mechanic/ molecular mechanical (QM/MM) method is employed in studying the screw and edge dislocation core structure of Tungsten. When absence of H, the widely used MEAM potential can successfully provide the core structure for both types of dislocations. However, no suitable W-H potential can describe the right structure when H is introduced. The coupling of the molecular dynamics and Ab initio calculation predicts a six-fold nondegenerate structure with a H atom added in screw dislocation, while in edge dislocation a partial dislocation appeared in the dislocation core.