复合稀土对CuZnAl形状记忆合金力学性能的影响

采用定量金相、拉伸试验、电子探针和扫描电镜等方法，研究了复合稀土对CuZnAl合金晶粒尺寸、晶粒生长动力学、力学性能的影响。结果表明：复合稀土可明显细化合金晶粒，改善合金的力学性能，合金的拉伸断口形貌由未加复合稀土的沿晶断裂变为韧窝状塑性断口，同时保持合金的记忆性能。微观分析表明：复合稀土富集在CMZnAl合金的晶界上，阻碍晶粒长大。讨论了晶粒细化机制以及合金力学性能提高的原因。

Effects of mischmetal on mechanical properties of CuZnAl shape memory alloy

With the help of quantitative metallography, tensile test, electron probe method and scan electron microscopy, the influences of mischmetal on the grain size, dynamics of grain growth and mechanical properties of CuZnAl shape memory alloy were investigated. The results show that mischmetal can refine grains greatly, improve the mechanical properties remarkably and change the tensile fracture type from brittle bordered grains to plastic under the condition of maintaining shape memory properties. Moreover microstructures reveal that mischmetal which accumulates on the grain boundaries can restrain grains' growing. In addition, the mechanisms of refining grain size and improving mechanical properties are also discussed.