Fabrication of Ti–Nb alloys by powder metallurgy process and their shape memory characteristics
Fabrication of Ti–Nb alloys by powder metallurgy process and their shape memory characteristics
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DOI：
10.1016/j.jallcom.2011.12.166
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发表时间：
2013-11
影响因子：
6.2
通讯作者：
A. Terayama;N. Fuyama;Y. Yamashita;I. Ishizaki;H. Kyogoku
中科院分区：
文献类型：
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作者：
A. Terayama;N. Fuyama;Y. Yamashita;I. Ishizaki;H. Kyogoku
采用粉末冶金工艺制备了Ti-Nb基形状记忆合金。研究了Ta、Al、Sn三元合金化和冷加工对Ti-Nb基合金形状记忆性能的影响。用脉冲电流烧结机烧结了成分为Ti-22at%Nb和Ti-22at%Nb-4at%X(X=0.Ta，Al，Sn)的混合元素粉末。为获得均匀的组织，进行了固溶处理。结果表明，固溶处理的Ti-22at%Nb合金在300K时由α“和β相组成，合金的马氏体相变起始温度低于相同成分的变形合金。Ti-22at%Nb-4at%Al合金在应力-应变曲线上表现出类似超弹性的行为，而在其他成分的固溶处理合金中则没有观察到这种超弹性行为。为了改善固溶处理的Ti-22At%Nb合金的形状记忆性能，对合金进行了减薄95%的冷轧。冷轧后退火的Ti-22At%Nb合金由于β织构的形成而表现出超弹性行为。合金在等温拉伸后表现出双向形状记忆效应。
Ti–Nb based shape memory alloys were fabricated by powder metallurgy (PM) process. The effects of ternary alloying additions of Ta, Al and Sn and cold working on the shape memory characteristics of the Ti–Nb based alloys were investigated. The mixed elemental powders at compositions of Ti–22 at%Nb and Ti–22 at%Nb–4 at%X (X = Ta, Al and Sn) sintered by a pulse-current sintering equipment. The solution-treatment was carried out to obtain homogeneous microstructure. As a result, the solution-treated Ti–22 at%Nb alloy consisted of α″ and β phases at 300 K. The martensitic transformation start temperature of the Ti–22 at%Nb alloy was lower than that of the wrought alloy of the same composition. The Ti–22 at%Nb–4 at%Al alloy indicated a superelastic-like behavior in the stress–strain curve, but the superelastic behavior could not be observed in the solution-treated alloys of other compositions. To improve the shape memory properties of the solution-treated Ti–22 at%Nb alloy, the alloys were cold-rolled at a reduction of 95% in thickness. The Ti–22 at%Nb alloy annealed after cold-rolling showed superelastic behavior due to formation of texture of β-phase. The alloy showed a two-way shape memory effect after isothermal tensile test.