Ca对Mg-Gd-Y-Zn-Zr合金热变形行为及热加工性能的影响

Effect of Ca-addition on Hot deformation Behavior and Workability of Mg-Gd-Y-Zn-Zr Alloy

摘要:

本文利用Gleeble3500热模拟试验机研究了Ca对Mg-Gd-Y-Zn-Zr合金在变形温度573~723K，应变速率0.001~1s-1的热变形行为及热加工性能的影响。结果表明：Ca增大了合金的流变应力及变形激活能，扩宽了加工安全区及最佳加工区范围，但降低了最大功率耗散因子及动态再结晶程度。结合激光共聚焦显微镜分析了合金热压缩后组织，验证了热加工图的准确性，并制定了合理的热加工工艺，Mg-Gd-Y-Zn-Zr合金的最佳加工区域为：应变速率0.001~0.01s-1，温度623~723K。根据最佳加工工艺参数获得了表面质量良好，无变形缺陷的等温锻造合金。

Abstract:

In this paper, effect of Ca on hot deformation behavior and workability of Mg-Gd-Y-Zn-Zr alloy were investigated by Gleeble 3500 thermal simulation tester conducted at a temperature ranging from 573K to 723K and strain rate varying from 0.001s-1 to 1s-1. It’s indicated that the addition of Ca increased the flow stress and hot deformation active energy, widened the range of processing stable zone and the optimal processing zone, but decreased the maximum power dissipation efficient, and inhibited the dynamic recrystallization. Combined the microstructure after thermal compression which was analyzed by laser confocal microscopy, the accuracy of the processing map was verified. The optimized hot processing parameters of Mg-Gd-Y-Zn-Zr were formulated, namely strain rate ranging from 0.001s-1 to 0.01s-1, temperature ranging from 623K to 723K. Depending on the optimum processing parameters, an isothermal forged magnesium alloy with good quality and no deformation defects was fabricated.