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详细地研究了Ni56Mn25-xCrxGa19(x=0,2,4,6)合金的微观组织结构、马氏体相变特性、力学性能及形状记忆效应。结果表明:当x=0时,合金呈现出单一的四方结构马氏体相;当x≥2时,合金的微观组织为包含马氏体相和γ相的双相结构;随着Cr元素的增加,合金的马氏体相变温度逐渐降低,其峰值温度从x=0时的401℃降低到x=6时的197℃。热轧和拉伸试验表明:通过添加Cr元素在合金微观组织中引入γ相可有效地提高合金的热加工性能和塑性,x≥4的合金可通过常规热轧得到表面状态良好的1mm厚的片材,合金的拉伸应力和应变在x=4和6时分别为497MPa,8%和454MPa,5.5%;x=4的合金在残余应变为4.5%时可得到2.7%的形状记忆回复,而x=6的合金在残余应变为3.5%时的可回复应变为1.9%。
The microstructure, martensitic transformation, mechanical properties and shape memory effect of Ni56Mn25-xCrxGa19 (x = 0, 2, 4, 6) The results show that when x = 0, the alloy exhibits a single tetragonal martensite phase. When x ≧ 2, the microstructure of the alloy is a dual phase structure including martensite phase and γ phase. With the increase of Cr content Increases, the martensitic transformation temperature of the alloy gradually decreases, and the peak temperature decreases from 401 ℃ at x = 0 to 197 ℃ at x = 6. The results of hot rolling and tensile tests show that the addition of Cr can effectively improve the hot workability and plasticity of the alloy by introducing γ phase into the alloy microstructure. The alloy with x≥4 can be obtained by conventional hot rolling to obtain a 1mm thick The tensile stress and strain of sheet and alloy are 497MPa, 8% and 454MPa, 5.5% at x = 4 and 6, respectively. The shape memory recovery of 2.7% is obtained when the residual strain is 4.5% The restorable strain of the alloy with x = 6 at the 3.5% residual strain was 1.9%.