Ni-free Ti-based shape memory alloy with superior superelasticity is promising and attractive for biomedical applications. In this study, Ti-18Zr-12.5Nb-2Sn (at.%) alloy fibers were prepared by rapid solidification method and then the effect of various heat treatments on phase constitutions, microstructures, mechanical properties, and superelasticity was investigated by means of X-ray diffraction (XRD), optical microscope (OM), transmission electron microscope (TEM) and tensile test. α phase was observed in the 673 K and 773 K annealed alloy fibers, leading to the degraded ductility. The total recovery strain at room temperature decreased, grain size and transformation temperature increased with increasing annealing temperature from 873 K to 1173 K. Athermal ω was observed in the 1173 K annealed alloy fibers. A good combination of clear superelasticity and high yield stress was achieved by annealing at 873 K followed by aging at 573 K due to the combined effect of the age-hardening caused by isothermal ω phase and small grain size, which indicates these alloy fibers have a good potential in biomedical applications.

具有超强弹性的无镍Ti基形状记忆合金在生物医学应用中是有前途且有吸引力的。在这项研究中，通过快速凝固方法制备了Ti-18Zr-12.5Nb-2Sn（at。％）合金纤维，然后用X射线研究了各种热处理对相组成，显微组织，力学性能和超弹性的影响。射线衍射（XRD），光学显微镜（OM），透射电子显微镜（TEM）和拉伸试验。在673 K和773 K退火合金纤维中观察到α相，导致延展性降低。随着退火温度从873 K增加到1173 K，室温下的总恢复应变降低，晶粒尺寸和相变温度增加。在1173 K退火合金纤维中观察到无热ω。