Enhanced impact toughness of magnesium alloy by grain refinement

The impact toughness of Mg–3Al–Zn alloy was systematically investigated with the focus on the effect of grain size. The impact toughness is greatly improved as the mean grain size is reduced to less than 3 μm, because the dynamic strength and dynamic plastic deformation ability are greatly enhanced. The superior dynamic strength of fine-grained samples may be explained in terms of grain size effect, and the high dynamic plastic deformation ability probably results from the suppression of twinning.