Enhancing yield strength by suppressing detwinning in a rolled Mg-3Al-1Zn alloy with {10(1)over-bar2} twins

Abstract

A remarkable improvement in the tensile yield strength of rolled Mg-3Al-1Zn alloy with pre-existing {10 (1) over bar2} twins was achieved by inducing double twinning through compression deformation. The resulting formation of {10 (1) over bar2}-{10 (1) over bar2} double twins inside pre-existing {10 (1) over bar2} twin bands effectively suppressed the detwinning of pre-existing twins during subsequent deformation. This in turn led to a change in the dominant deformation mode from detwinning to slip, significantly increasing the yield strength. The mechanisms behind this behavior are considered to be a combination of the redistribution of residual tensile stress within pre-existing twins, refinement of pre-existing twins by double twins, a change in texture due to double twinning and a loss of coherency at twin boundaries. (C) 2014 Elsevier B.V. All rights reserved.