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

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 (kS) decreased gradually due to continuous activation of non-basal slips, while that for twinning-mediated-plasticity (kT) increased rapidly owing to increase in twin number and density, corresponding to grains below and above the medium-size of ∼22 μm respectively.

► Deformation mechanisms for rolled AT33 alloy strongly depend on grain sizes.
► For grains of ∼6–22 μm, tensile deformation is mainly dominated by dislocation-slip.
► For grains of ∼22–41 μm, however, which turns to be mediated by deformation-twinning.
► H–P slope for slip-controlled-plasticity decreases due to non-basal slip activation.
► While it for twinning-mediated-plasticity increase owing to increase in twin numbers.