Screw dislocation core structure and plastic deformation of BCC Metals

Abstract

The core structure and an energy distribution around a screw dislocation core in model bcc lattice have been investigated in both unstressed and stressed states to clarify the controlling factors which determines the core type and the shape of PEIERLS potential. In the case of iron total four types of core structure were obtained, namely, unpolarized, polarized, split and high energy position and the shape of PEIERLS potential was so-called camel hump type which gives a steadfast explanation for the presence of a hump on the yield stress — temperature curve of iron single crystal. The calculated results for the spatial distribution of the PEIERLS potential around a core show that the range of distribution is relatively small in the low PEIERLS stress case (iron), but is large in high PEIERLS stress case (vanadium).