Enhanced superplasticity of magnesium alloy AZ31 obtained through equal-channel angular pressing with back-pressure
- 290 Downloads
Excellent superplastic elongations (in excess of 1,200%) were achieved in a commercial cast AZ31 alloy processed by low temperature equal-channel angular pressing (ECAP) with a back-pressure to produce a bimodal grain structure. In contrast, AZ31 alloy processed by ECAP at temperatures higher than 200 °C showed a reasonably uniform grain structure and relatively low ductility. It is suggested that a bimodal grain structure is advantageous because the larger grains contribute to strain hardening thus delaying the onset of necking, while grain boundary sliding associated with small grains provides a stabilizing effect due to enhanced strain rate sensitivity.
KeywordsMagnesium Alloy Solution Heat Treatment Tensile Ductility Magnesium Alloy AZ31 Superplastic Behaviour
This work was supported by the Australian Research Council through Linkage International Grant no. LX0668485. The authors would like to express their gratitude to Professor T.G. Langdon for useful discussions.