This study investigated the effect of tensile deformation on the transformation behaviour of NiTi within the constrained environment of NiTi–Nb composites. Particular attention is given to the deformation-induced stabilisation of the stress-induced martensite manifested as the increase of the reverse transformation temperature. Two different forms of the NiTi–Nb composites were used, including nanowires and microparticles, in comparison with the single-component binary NiTi alloy. This stabilisation effect has been reported for NiTi in the literature. The effect is attributed to the changes in the internal elastic and plastic states of the martensite variant structure caused by the deformation. The NiTi–Nb nanocomposites present different internal mechanics environments. It was found that the presence of a second phase within the NiTi matrix hinders the lattice distortion martensitic transformation, enlarging its hysteresis in the order of the binary NiTi, the NiTi–Nb microparticle composite and the NiTi–Nb nanowire composite. After deformation, the NiTi–Nb microparticle composite exhibited the highest stabilisation effect, followed by the NiTi–Nb nanowire composite and then the binary NiTi alloy. These contrasting observations are attributed to dual effects of the Nb inclusions within the NiTi matrix, to obstruct the lattice distortions of the martensitic transformation, and to retain elastic strains and thus stresses that may assist and resist a transformation depending on their relative directions.

本研究调查了在 NiTi-Nb 复合材料的约束环境中拉伸变形对 NiTi 转变行为的影响。特别注意应力诱发马氏体的变形诱发稳定化，表现为逆相变温度的升高。与单组分二元 NiTi 合金相比，使用了两种不同形式的 NiTi-Nb 复合材料，包括纳米线和微粒。文献中已经报道了镍钛的这种稳定效果。该效应归因于变形引起的马氏体变体结构的内部弹性和塑性状态的变化。NiTi-Nb 纳米复合材料呈现不同的内部力学环境。发现 NiTi 基体中第二相的存在阻碍了晶格畸变马氏体转变，按照二元 NiTi、NiTi-Nb 微粒复合材料和 NiTi-Nb 纳米线复合材料的顺序扩大了其滞后。变形后，NiTi-Nb 微粒复合材料表现出最高的稳定效果，其次是 NiTi-Nb 纳米线复合材料，然后是二元 NiTi 合金。这些对比观察归因于 NiTi 基体中 Nb 夹杂物的双重作用，阻碍了马氏体转变的晶格畸变，并保留了弹性应变和应力，这些应力可能有助于和抵抗转变，具体取决于它们的相对方向。NiTi-Nb 微粒复合材料和 NiTi-Nb 纳米线复合材料。变形后，NiTi-Nb 微粒复合材料表现出最高的稳定效果，其次是 NiTi-Nb 纳米线复合材料，然后是二元 NiTi 合金。这些对比观察归因于 NiTi 基体中 Nb 夹杂物的双重作用，阻碍了马氏体转变的晶格畸变，并保留了弹性应变和应力，这些应力可能有助于和抵抗转变，具体取决于它们的相对方向。NiTi-Nb 微粒复合材料和 NiTi-Nb 纳米线复合材料。变形后，NiTi-Nb 微粒复合材料表现出最高的稳定效果，其次是 NiTi-Nb 纳米线复合材料，然后是二元 NiTi 合金。这些对比观察归因于 NiTi 基体中 Nb 夹杂物的双重作用，阻碍了马氏体转变的晶格畸变，并保留了弹性应变和应力，这些应力可能有助于和抵抗转变，具体取决于它们的相对方向。