Hot Compression Deformation Behavior and Processing Maps of Mg-Zn-Mn(-Sn)-Ca Alloy

Abstract:

The hot compression deformation behavior of Mg-6Zn-1Mn-0.5Ca (ZM61-0.5Ca) and Mg-6Zn-1Mn-2Sn-0.5Ca (ZMT612-0.5Ca) alloys was investigated at deformation temperatures ranging from 250 ℃ to 400 ℃ and strain rates varying from 0.001 s^–1 to 1 s^–1. The results show that the addition of Sn promotes dynamic recrystallization (DRX), and CaMgSn phases can act as nucleation sites during the compression deformation. Flow stress increases with increasing the strain rate and decreasing the temperature. Both the ZM61-0.5Ca and ZMT612-0.5Ca alloys exhibit obvious DRX characteristics. CaMgSn phases can effectively inhibit dislocation motion with the addition of Sn, thus increasing the peak ?ow stress of the alloy. The addition of Sn increases the hot deformation activation energy of the ZM61-0.5Ca alloy from 199.654 kJ/mol to 276.649 kJ/mol, thus improving the thermal stability of the alloy. For the ZMT612-0.5Ca alloy, the optimal hot deformation parameters are determined to be a deformation temperature range of 350–400 ℃ and a strain rate range of 0.001–0.01 s^–1.