Deformation dynamics in pre-twinned Mg-3Al-1Zn alloy: A synchrotron X-ray study

Abstract

We investigate the deformation dynamics in pre-twinned Mg-3Al-1Zn alloy under uniaxial compression based on in situ synchrotron X-ray diagnostics. Stress-strain curves, strain field mapping and X-ray diffraction are achieved simultaneously. The same measurements are conducted on the as-received Mg alloy for comparison. Massive {101¯2}–{101¯2} double twinning is observed in preexisting twins of the pre-twinned specimen, and abundant {101¯2} extension twins are activated in the as-received specimen. The {101¯2} extension twinning in the as-received specimen can rapidly boost strain hardening rate by slowing down the process of strain localization. The {101¯2}–{101¯2} double twinning does not lead to significant reduction in the rate of strain localization, and thus the corresponding increase in strain hardening rate is modest.