Dynamic properties of an ultrafine-grained Mg-Zn-Zr alloy

The effect of ultrafine-grained structure formation in Mg-Zn-Zr alloy ZK60 on its mechanical response was investigated at strain rates ranging from quasi-static to dynamic regimes. The study demonstrated that the strength characteristics of the material rise significantly with increasing strain rate, while its ductility is reduced. These effects are particularly pronounced in the dynamic loading regime, at strain rates in the (1-5) × 10² s^-1 range. In the ultrafine-grained alloy ZK60, the energy absorption per unit volume, W, is enhanced by grain refinement by a factor as high as eight for the highest strain rate of 5 × 10² s^-1 investigated. The analysis is focused on the microstructure features that bring about the observed improvement of the tensile characteristics, as well as the deformation and fracture modes prevalent at different strain rates. The results obtained contribute to the exploration and understanding of dynamic behaviour of magnesium alloys.