Martensitic transition and superelasticity of Co–Ni–Al ferromagnetic shape memory alloys with β + γ two-phase structure
Martensitic transition and superelasticity of Co–Ni–Al ferromagnetic shape memory alloys with β + γ two-phase structure
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DOI：
10.1016/j.msea.2006.05.021
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发表时间：
2006-11
期刊：
影响因子：
6.4
通讯作者：
Yuuki Tanaka;K. Oikawa;Y. Sutou;T. Omori;R. Kainuma;K. Ishida
中科院分区：
文献类型：
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作者：
Yuuki Tanaka;K. Oikawa;Y. Sutou;T. Omori;R. Kainuma;K. Ishida
本文系统地研究了Co-Ni-Al β单相和β+γ两相合金的马氏体相变和磁相变。β单相合金的居里温度TC和马氏体相变温度对Ni和Al的成分敏感。TC值随着Ni和Al含量的减少而增加，而马氏体转变开始温度Ms随着Ni含量的减少和Al含量的增加而降低。β+γ两相合金的Tc和Ms与退火温度有关，这是由于与γ相平衡的β相的化学成分发生了变化，随着退火温度的升高而增大。此外，还研究了Co-Ni-Al多晶β+γ合金在拉伸载荷下的超弹性。结果表明，β+γ两相合金的SE性能强烈依赖于β晶粒的平均尺寸和γ相的体积分数。因此，在具有大β晶粒的板状试样中实现了约6.3%的最大恢复SE应变。
The martensitic and magnetic phase transitions of Co–Ni–Al β single and β+γ two-phase alloys have been systematically investigated. The Curie temperature TCand the martensitic transition temperature of the β single-phase alloys are sensitive to the Ni and Al compositions. The value of TCincreases with decreasing both the Ni and Al contents, while the martensitic transition starting temperature Msdecreases with decreasing the Ni content and with increasing the Al content. TCand Msof the β+γ two-phase alloy depend on the annealing temperature due to the variation of the chemical composition of β phase equilibrated with γ phase, increasing by the increase of annealing temperature. In addition, the superelasticity (SE) in tensile loading of the Co–Ni–Al polycrystal β+γ alloys have been investigated. It was found that the SE properties in the β+γ two-phase alloys strongly depend on the average β grain size as well as the volume fraction of γ phase. Consequently, the maximum recovery SE strain of about 6.3% was achieved in a sheet specimen with the large β grains.