An intrinsic two-way shape memory effect with a fully recoverable strain of 1.0 % was achieved in an as-prepared Ni₅₀Mn_37.5Sn_12.5 metamagnetic shape memory microwire fabricated by Taylor-Ulitovsky method. This two-way shape memory effect is mainly owing to the internal stress caused by the retained martensite in austenite matrix, as revealed by transmission electron microscopy observations and high-energy X-ray diffraction experiments. After superelastic training for 30 loading/unloading cycles at room temperature, the amount of retained martensite increased and the recoverable strain of two-way shape memory effect increased significantly to 2.2 %. Furthermore, a giant recoverable strain of 11.2 % was attained under a bias stress of 300 MPa in the trained microwire. These properties confer this microwire great potential for micro-actuation applications.

在制备的Ni ₅₀ Mn _37.5 Sn _12.5中获得了固有的双向形状记忆效应，具有1.0％的完全可恢复应变通过Taylor-Ulitovsky方法制备的超磁性形状记忆微丝。这种双向形状记忆效应主要是由于透射电镜观察和高能X射线衍射实验所揭示的，由于马氏体残留在奥氏体中而引起的内部应力。在室温下进行30次加载/卸载循环的超弹性训练后，马氏体的保留量增加，双向形状记忆效应的可恢复应变显着提高到2.2％。此外，在受过训练的微丝中，在300 MPa的偏压力下，可恢复的应变高达11.2％。这些特性为微型驱动应用提供了巨大的潜力。