Abstract

The phase transformation and recovery stress of pre-deformed Ni₄₇Ti₄₄Nb₉ alloy are systematically investigated during constrained heating, cooling and thermal cycling. Recovery stress is determined by a phase transformation, thermal expansion, and contraction. Reverse martensitic transformation occurs during constrained heating and then results in a sharp increase in the recovery stress. Meanwhile, the wide phase transformation hysteresis shrinks during thermal cycling. A few martensitic transformations gradually occur across a wide temperature range during constrained cooling, resulting in a negative decreasing stage or a wide plateau of recovery stress. When cooled further to a critical value of 20 °C, the recovery stress and temperature follow the Clausius–Clapeyron equation, and large amounts of martensitic transformations appear, resulting in the sharp decrease of the recovery stress.

中文翻译：

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Ni 47 Ti 44 Nb 9合金受约束的加热和冷却过程中的相变和恢复应力

抽象的

预变形Ni ₄₇ Ti ₄₄ Nb ₉的相变和恢复应力在受限制的加热，冷却和热循环过程中对合金进行了系统的研究。恢复应力取决于相变，热膨胀和收缩。马氏体逆相变在受限制的加热过程中发生，然后导致恢复应力急剧增加。同时，宽相变磁滞在热循环期间缩小。在约束冷却期间，在较宽的温度范围内会逐渐发生一些马氏体相变，从而导致负的下降阶段或恢复应力的平稳期。当进一步冷却到20°C的临界值时，恢复应力和温度遵循Clausius-Clapeyron方程，并且出现大量的马氏体相变，导致恢复应力急剧下降。