Ab initio modeling of slip activity in body-centered cubic chromium

Abstract

Slip activity in body-centered cubic chromium is modeled by means of ab initio calculation of screw dislocations core properties and Peierls potential. As dislocations having 1/2<111> Burgers vector and also <100>, both gliding in {110} crystallographic planes have been reported experimentally, both screw dislocations are modeled. A generalized yield criterion incorporating physical ingredients necessary to account for deviations from the Schmid law is obtained for <111>{110} and <100>{110} slip systems. We report a broad range of crystal orientations for which <100> screw dislocations are easier to activate than the conventional 1/2<111> in tension and compression. These results hold for both the non-magnetic and antiferromagnetic phases of body-centered cubic chromium, with only a marginal effect of magnetism.