The effects of nanosegregation arising from low-temperature aging (LTA) on cyclic response of Ti-50.9 at.% Ni are investigated. Hybrid Monte Carlo/Molecular Dynamics (MC/MD) simulation indicates that the most pronounced nanosegregation is achieved by LTA at 523 K. MD simulation shows Ni cluster can impede the advancement of {011}<100> dislocations, which prevail the slipping activity of NiTi, during both forward and reverse transformations due to pinning effect, so the resistance to functional degradation is promoted significantly. Experiments demonstrate that LTA at 523 K for 2 h and the resultant nanosegregation can greatly improve the superelastic stability of nanocrystalline Ti-50.9 at.% Ni, the residual strain is reduced by 50 % and the dissipation energy is increased by 200 % in LTAed sample after 50 loading-unloading cycles. These insights open possibilities for the design of SMA with outstanding cyclic stability via the combination of nanocrystalization and nanosegregation.

中文翻译：

---

通过低温时效提高 Ti-50.9 at.% Ni 形状记忆合金中的纳米偏析的超弹性稳定性

研究了低温老化 (LTA) 引起的纳米偏析对 Ti-50.9 at.% Ni 循环响应的影响。混合蒙特卡罗/分子动力学 (MC/MD) 模拟表明，LTA 在 523 K 时实现了最明显的纳米偏析。MD 模拟表明 Ni 簇可以阻碍 {011}<100> 位错的进展，而这种位错占主导地位的滑移活动NiTi在正向和反向转变过程中由于钉扎效应，因此显着提高了对功能退化的抵抗力。实验表明，在523 K下进行2 h的LTA以及由此产生的纳米偏析可以极大地提高纳米晶Ti-50.9 at.% Ni的超弹性稳定性，LTAed样品的残余应变降低了50 %，耗散能提高了200 % 50次加载-卸载循环后。这些见解为通过纳米结晶和纳米偏析的结合设计具有出色循环稳定性的 SMA 提供了可能性。