钛基高温形状记忆合金进展综述

Research Progress of Titanium-based High-temperature Shape Memory Alloy

形状记忆合金凭借其独特的形状记忆效应和超弹性成为了重要的金属智能材料,在航空航天、电子、汽车和医疗等领域展现出巨大的应用价值。二元近等原子比镍钛合金是最为成熟的形状记忆合金材料,但是镍钛合金难以在很高的温度环境下(>100℃,373 K)实现应用。以航空航天、核反应堆等为代表的高温服役环境迫切需要具有高相变温度(>373 K)且综合性能良好的形状记忆合金,因此,发展高温形状记忆合金是本领域面临的研究重点和难点。近年来,科研工作者们以新型钛基合金为研究对象,通过合金化元素设计,获得具有高马氏体相变温度的形状记忆材料,发展出Ti-Ta基、Ti-Zr基、Ti-Nb基、Ti-Mo基等新型高温形状记忆合金体系。在满足高温相变特性的基础上,这些合金体系体现出不同的性能特点,例如Ti-Ta基合金利用Ta元素有效抑制ω相的析出而提高合金塑性,Ti-Nb基合金具有良好的加工成型能力。此外,以Pd、Pt、Au等贵金属为合金化元素可以进一步提高材料的相变温度,加入Sn、Al、Ga等元素则可以适当降低相变温度,并改善材料的力学性能和功能特性。本文综述了Ti-Ta基、Ti-Zr基、Ti-Nb基、Ti-Mo基等主要钛基高温形状记忆合金体系的研究进展,着重分析了合金化元素对合金相变温度、形状记忆效应、力学性能的影响规律,对各类合金的性能优势及缺点进行了全面总结,提出了高温形状记忆合金研究中存在的问题和未来发展方向。

Shape memory alloys have become important smart materials due to their unique shape memory effect and superelastic properties,showinggreat promising in aviation,aerospace,electronics,automotive and medical applications. The binary near-equiatomic nickel-titanium alloy is one of the most well-developed shape memory materials,but it is very difficult to be used at very high temperature( >100 ℃,373 K). The hightemperature service environment represented by aviation,aerospace,nuclear reactors,etc. urgently requires shape memory alloy materials with high phase transformation temperature and good combined properties. Therefore,the development of high-temperature shape memory alloy has become a research focus and difficulty in this field. In recent years,researchers have used the new titanium-based alloys as research objects to obtain shape memory materials with high martensitic transformation temperature through the design of alloying elements,and developed new hightemperature shape memory alloy systems such as Ti-Ta based,Ti-Zr based,Ti-Nb based and Ti-Mo based alloys. On the basis of satisfying the high temperature phase transformation characteristics,these alloy systems exhibit different performance characteristics. For example,Ti-Ta based alloys can effectively inhibit the precipitation of ω phase by Ta element and improve the plasticity. Ti-Nb based alloys have good processing ability. In addition,the alloying elements such as Pd,Pt and Au can be used in alloys to further increase the phase transition temperature. The addition of elements such as Sn,Al,and Ga can appropriately lower the alloy transformation temperature and improve its mechanical properties and functional properties.In this paper,the research progresses of several high-temperature shape memory alloy systems such as Ti-Ta based,Ti-Zr based,Ti-Nb based and Ti-Mo basedalloys are reviewed. The effects of alloying elements on phase transformation temperature,shape memory effect and mechanical properties of alloys are analyzed. This paper gives comprehensive summary of the performance advantages and defects of various alloys,and proposes the development direction of new high temperature shape memory alloy materials in the future.