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采用电阻法和OM等手段研究了不同温度区间的热循环对Fe-14Mn-5.5Si-8Cr-5Ni合金微观组织和形状记忆效应的影响。结果表明:298 K～353 K、520 K、773 K和77 K～773 K热循环1次后,合金形状回复率均大幅度提高;298～773 K循环5次后的形状回复率提高了26%,77～773 K热循环5次后的形状回复率提高了36%。热循环显著减少了因淬火热应力导致的热诱发ε马氏体量,并且热诱发ε马氏体的逆转变向基体引入了大量的堆垛层错。与固溶态相比,热循环后再变形不仅使α’马氏体的数量显著减少,而且应力诱发ε马氏体以区域化的方式形成,因而合金的形状记忆效应显著提高。77～773 K的热循环比298～773 K的热循环更能显著提高合金形状记忆效应的原因是由于其引入了更多的堆垛层错。
The effects of thermal cycling in different temperature ranges on the microstructure and shape memory effect of Fe-14Mn-5.5Si-8Cr-5Ni alloy were investigated by resistance method and OM method. The results showed that the shape recovery rates of the alloys increased greatly after thermal cycles of 298 K ~ 353 K, 520 K, 773 K and 77 K ~ 773 K, respectively. The shape recovery rates of the alloys after 298 ~ 773 K cycles increased by 26 %, 77 ~ 773 K heat cycle after 5 times the shape recovery rate increased by 36%. Thermal cycling significantly reduces the amount of heat-induced ε-martensite due to the thermal stress induced by quenching, and the heat-induced reversal of ε-martensite introduces a large number of stacking faults to the substrate. Compared with the solid solution state, re-deformation after thermal cycling not only significantly reduces the amount of α ’martensite, but also forms stress-induced ε martensite in a localized manner. Thus, the shape memory effect of the alloy is significantly improved. The thermal cycling from 77 K to 773 K can significantly improve the shape memory effect of the alloy due to the thermal cycling of 298 K to 773 K due to the introduction of more stacking faults.