Grain refinement of a commercial magnesium alloy for superplastic forming

Superplastic forming was performed at a high strain rate of 10(-2) s(-1) for a commercial ZK60 magnesium. The relatively high forming temperature of 673 K was decided from the superplastic characteristics owing to its grain size similar to 5 mum. In order to prevent the grain growth during the high temperature superplasticity, the possibility of low temperature superplasticity(LTSP) in magnesium was derived. The required gain size for high strain rate superplasticity(HSRS) at the low homologous temperature was estimated, and the fabrication techniques to develop the fine-grained structure were discussed.