In the present study, the electron concentration, bond order and metallic average d-electron orbital energy level of Ti-Nb-Hf shape memory alloys were controlled by adjusting the Hf content, which further determined the phase constituents and phase stability. The Ti-Nb-Hf shape memory alloys with various Hf contents were composed of the α´´ martensite phase and β phase, regardless of Hf contents. With increasing Hf content, the martensitic transformation temperature (Ap) slightly increased. Hf addition could enhance the strength and optimize the strain recovery characteristics. A higher strength and larger recoverable strain can be obtained in Ti-Nb shape memory alloy modified by 2 at.% Hf due to grain refinement, precipitation strengthening and solution strengthening. Training can achieve perfect superelasticity with a completely recoverable strain of approximately 2%. In conclusion, the perfect combination of damping capacity and strain recovery characteristics can be attained by tailoring the Hf content in Ti-Nb-Hf shape memory alloys.

本研究通过调节 Hf 含量来控制 Ti-Nb-Hf 形状记忆合金的电子浓度、键序和金属平均 d 电子轨道能级，进一步确定了相组成和相稳定性。不同Hf含量的Ti-Nb-Hf形状记忆合金由α´´马氏体相和β相组成，与Hf含量无关。随着 Hf 含量的增加，马氏体转变温度 ( Ap) 略有增加。添加 Hf 可以提高强度并优化应变恢复特性。2 at.% Hf改性的Ti-Nb形状记忆合金由于晶粒细化、析出强化和固溶强化，可以获得更高的强度和更大的可恢复应变。训练可以达到完美的超弹性，完全可恢复的应变约为 2%。总之，通过调整 Ti-Nb-Hf 形状记忆合金中的 Hf 含量，可以实现阻尼能力和应变恢复特性的完美结合。