Influence of grain size on deformation mechanisms in rolled Mg-3Al-3Sn alloy at room temperature

摘要

The deformation mechanisms for rolled Mg-3Al-3Sn alloys were strongly dependent on grain sizes at room temperature. For grain sizes of ～6-22 μm, the deformation in tension was mainly dominated by dislocation-slip, which, however, turned to be mediated by deformation-twinning for those of ～22-41 μm. Moreover, as deformation proceeded, Hall-Petch slopes for slip-controlled-plasticity (k_S) decreased gradually due to continuous activation of non-basal slips, while that for twinning-mediated-plasticity (k_T) increased rapidly owing to increase in twin number and density, corresponding to grains below and above the medium-size of ～22 μm respectively.