La+Ce复合细化CuZnAl形状记忆合金

CuZnAl Shape Memory Alloy Refined with Complex Rare Earth La+Ce

通过金相观察、拉伸和弯曲试验、电阻测量、电子探针和扫描电镜等方法， 研究了Ｌａ＋ Ｃｅ 对ＣｕＺｎＡｌ 形状记忆合金的微观结构和性能的影响。结果表明， 复合添加微量稀土（Ｌａ∶Ｃｅ ＝ １∶１） ， 能够明显细化ＣｕＺｎＡｌ 形状记忆合金的晶粒组织， 提高合金的综合机械性能， 显著改善合金的冷加工性能。合金经过Ｌａ＋ Ｃｅ 复合细化后（ ＜０．１０ ％ ） ， 仍具有良好的形状记忆效应， 同时降低了马氏体相变温度滞后宽度， 并使马氏体不易稳定化。微观分析表明， 复合稀土富集在ＣｕＺｎＡｌ 合金的晶界上， 阻碍晶粒长大，有利于ＣｕＺｎＡｌ 合金性能的提高， 但稀土加入量＞ ０．１０ ％ 后， 合金的记忆性能降低。

The effects of complex rare earth La+Ce on properties of CuZnAl shape memory alloys were studied by optical examination, tensile test, electrical resistivity measurement and bending test, EDS and SEM. The test results show that the grain size of CuZnAl SMA may be refined effectively, and the mechanical properties are improved considerably by complex rare earth La+Ce(La∶Ce=1∶1) addition. Meanwhile, the excellent memorial properties remain unchanged. The results of microanalyses indicate that the complex rare earth segregated on grain boundary, and thus impedes the grain growth, leading to the improvement of mechanical properties of CuZnAl SMA. As the amount of complex rare earth La+Ce is higher than 0 10%, the memorial properties worsened.