Deformation processes in [112¯0]-textured nanocrystalline Mg by molecular dynamics simulation

Abstract

Plastic deformation of nanocrystalline Mg is studied using molecular dynamics simulation. In a $\left[11\overline{2}0\right]$-textured structure, slip and twinning behaviors are observed during tensile loading. Various twinning and slip process are identified, with basal slip and tensile $\left\{10\overline{1}2\right\}〈10\overline{1}1〉$ twinning being dominant. For grain sizes larger than ∼30 nm, basal slip occurs at a lower strain than twinning; for smaller grain sizes, twinning takes place at a lower strain than slip. For small grain sizes, the system generates partial dislocations; extended or full type dislocations are generated at high stress and large grain sizes. As the external stress increases, pyramidal 〈c + a〉 dislocations are also frequently generated, leading to a reduction in twinning activity. Whereas, under low stresses only the tensile twin is created at the grain boundaries, under high stress compressive twins are created at grain boundaries and in the interior of grains.