Atomistic study of pyramidal slips in pure magnesium single crystal under nano-compression

Abstract

Pyramidal slip mechanism plays an important role in c-axis micro-compression of hexagonal closed-packed metals. In this article, the detailed slip paths, respectively, on and planes in magnesium single crystal are given by molecular dynamics. The pyramidal slip on plane is suggested to consist of an edge-type partial dislocation and opposite basal movements on neighbouring basal planes, while the slip dissociation is achieved by two partial dislocations with a strip of stacking fault. Results imply that the slip on plane is more likely to nucleate with a relatively easy dissociation type comparing to the one on plane. No twinning is found under c-axis compression by examining the stepwise movement of atoms involved, fully supporting the recent experimental observations of micro-compression and the theoretical analysis on twinning formation proposed by our previous work.