On the Influence of Twinning and Detwinning on the Deformation of Mg at the Micron Scale

Abstract

The influence of twinning and detwinning on the constitutive mechanical response of Mg was investigated via microcompression tests of single crystalline pillars of nominal [0001] and [10-10] orientations, and bicrystalline pillars containing a single {1 0 1􀴤 2} twin boundary. The [0001] pillars exhibit the highest initial yield strength while the [10-10] and bicrystalline pillars initially yield at a significantly lower stress, at which twin nucleation and growth or migration commences. Depending on the extent of straining, the [10-10] and bicrystalline pillars exhibit a secondary yield point associated with the deformation of the newly formed [0001] oriented pillar. The mechanical results point to an anisotropy in the mechanical consequence of twin motion, as characterized through the comparison of the three micropillar orientations; a twin-mediated hardening is indicated by the relative stress-strain behavior.