Ti-Ni-Hf高温形状记忆合金的研究进展

Ti-Ni-Hf记忆合金因具有高相变温度、相对低廉的价格和高输出功等诸多优点而成为最具潜力的高温形状记忆合金之一。然而,Ti-Ni-Hf记忆合金基体强度低,变形过程中易优先发生塑性变形,从而使其可实现的可恢复应变远低于理论值。目前改善应变恢复特性的措施主要包括:热机械处理(冷轧+退火)、合金化、时效处理、制备单晶合金等。研究表明,Ti-Ni-Hf合金的应变恢复特性与微观组织结构密切相关。本文主要阐述了Ti-Ni-Hf记忆合金在近年来的最新研究进展,包含微观组织结构的演化规律、马氏体相变行为以及力学性能和应变恢复特性,并基于前期研究成果建立了微观组织结构-马氏体相变-力学与应变恢复特性的关联特性。当前,Ti-Ni-Hf高温形状记忆合金冷、热加工性能差是其广泛应用的瓶颈。因此,Ti-Ni-Hf高温记忆合金的粉末冶金和增材制造可能是未来研究的热点与重点。

Research progress in Ti-Ni-Hf high temperature shape memory alloys

Ti-Ni-Hf alloy is one of the most potential high temperature shape memory alloys due to the various advantages such as higher phase transformation temperature,relatively lower cost and larger output work.However,the plastic deformation takes place prior to the reorientation of martensitic variants due to the lower matrix strength,which results in the poor shape memory properties.To date,the measures of improving the strain recovery characteristics consist of thermo-mechanical treatment(cold rolling+annealing),alloying,aging treatment and fabrication of single crystal etc.It has been revealed that the strain recovery performances of Ti-Ni-Hf alloys are closely related to the microstructural features.In the present paper,the recent progress in the field of Ti-Ni-Hf high temperature shape memory alloy was presented,mainly consisting of microstructural evolution,martensitic transformation behaviour,mechanical properties and strain recovery features,moreover,the relationship between the microstructure,martensitic transformation as well as the mechanical and strain recovery characteristics was established,based on the previous research results.At present,the poor cold or hot workability of Ti-Ni-Hf high temperature shape memory alloy is the bottleneck which limits its extensive applications.Hence,the future research may focus on the powder metallurgy and additive manufacturing of Ti-Ni-Hf high temperature shape memory alloy.