Mg-Zn-Mn(-Sn)-Ca合金的热压缩变形行为及加工图

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

摘要:

研究了Mg-6Zn-1Mn-0.5Ca（ZM61-0.5Ca）和Mg-6Zn-1Mn-2Sn-0.5Ca（ZMT612-0.5Ca）合金在250~400 ℃和0.001~1 s^–1条件下的热压缩变形行为。结果表明：添加Sn促进了动态再结晶，CaMgSn相可作为压缩变形过程中的形核位点。流变应力随应变速率的增加和温度的降低而增大。ZM61-0.5Ca和ZMT612-0.5Ca合金具有明显的动态再结晶特征。加入Sn后，CaMgSn相能有效抑制位错运动，从而提高合金的峰值流变应力。Sn的加入使ZM61-0.5Ca合金的热变形活化能从199.654 kJ/mol提高到276.649 kJ/mol，提高了合金的热稳定性。ZMT612-0.5Ca合金的最佳热变形参数为变形温度350~400 ℃、应变速率0.001~0.01 s^–1。

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.