Mg-Gd-Y-Nd-Zr合金铸锭均匀化工艺研究

Research of homogenization process for Mg-Gd-Y-Nd-Zr alloy ingots

采用光学显微镜、DTA差热分析和能谱分析等方法研究了铸态Mg-Gd-Y-Nd-Zr合金的均匀化处理工艺。试验结果表明,该合金铸态存在大量的非平衡共晶相,由富含Gd、Y、Nd的富稀土相组成。经过不同的均匀化热处理制度处理后,其组织结构有了较大的变化,随均匀化温度升高和保温时间延长,共晶相逐渐消失,溶入基体。但基体的晶粒度也随之增大,表现为塑性增加,强度先增加后减少。该合金的最佳均匀化处理制度为530℃保温24 h。

Abstract： The homogenization process of as cast Mg-Gd-Y-Nd-Zr alloy have been studied by OM, DTA, and EDS techniques. The results showed that many non-equilibrium eutectics existed in the cast structure, which was composed with rare earth phases rich in Gd, Y and Nd. The microstructure changed greatly after dealing with different homogenization heat treatment. With the rising of homogenization temperature and soaking time, eutectics phase gradually disappeared and dissolved into the matrix. The grain sizes of the matrix became bigger, shown as increasing plasticity, as well as first-increasing and then-decreasing strength. The best homogenization processing of this alloy was soaking for 24h at 530 ℃.