Microstructure and phase transformation behavior of a new high temperature NiTiHf-Ta shape memory alloy with excellent formability
Microstructure and phase transformation behavior of a new high temperature NiTiHf-Ta shape memory alloy with excellent formability
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DOI：
10.1016/j.jallcom.2016.12.129
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发表时间：
2017-03
影响因子：
6.2
通讯作者：
R. Prasad;C. Park;Seong-Woong Kim;J. Hong;J. Yeom
中科院分区：
文献类型：
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作者：
R. Prasad;C. Park;Seong-Woong Kim;J. Hong;J. Yeom
研究了新型高温形状记忆合金Ni 49 Ti 36 Hf 15-xTa（x=0，3，6，9，12）的显微组织、力学性能和相变行为。Ni 49 Ti 36 Hf 15合金由（Ti，Hf）2Ni相组成，该相脆性大，与马氏体基体不相容。而Ta替代Hf的加入抑制了脆性（Ti，Hf）2Ni相的形成，并形成了白色富Ta相。添加Ta的Ni 49 Ti 36 Hf 15高温形状记忆合金的断面收缩率超过70%。对于最高达6at. %的较低Ta浓度，奥氏体转变温度远高于200 °C（473 K）;然而;在较高Ta浓度（即高于9at. %）下显著降低。Ta的加入对Ni 49 Ti 36 Hf 15合金的热变形行为和高温形状记忆性能有显著影响。本文对Ni_（49）Ti_（36）Hf_（15-x）Ta（x=0，3，6，9，12）高温形状记忆合金进行了详细的研究。
Microstructure, mechanical properties as well as phase transformation behavior of newly developed Ni49Ti36Hf15-xTa(x=0, 3, 6, 9, 12)high temperature shape memory alloys has been investigated. Ni49Ti36Hf15alloy consists of (Ti,Hf)2Ni phase which is brittle and incoherent with the martensite matrix. However, addition of Ta in place of Hf suppresses the brittle (Ti,Hf)2Ni phase formation with white Ta rich phase. More than 70% reduction in area has been observed in Ta added Ni49Ti36Hf15high temperature shape memory alloys. The austenitic transformation temperature is well above 200 °C (473 K) for lower Ta concentrations with up to 6 at. %; however; at higher Ta concentrations (i.e. above 9 at. %) decreases significantly. Overall, the addition of Ta greatly influences the hot deformation behavior and high temperature shape memory properties of Ni49Ti36Hf15alloy. The present paper discusses the detailed investigation on Ni49Ti36Hf15-xTa(x=0, 3, 6, 9, 12)high temperature shape memory alloys.