【摘要】 研究了时效工艺对FeMnSiCrNiNbC合金形状记忆效应、冷却到室温的回复应力以及Ms温度的影响,通过SEM分析了微观组织的变化。结果表明:在800℃时效时,与直接时效相比,10%室温形变后时效对合金的形状记忆效应、冷却到室温的回复应力以及Ms温度提高更加显著;形变后产生的晶体缺陷提供了NbC的形核位置,使NbC的析出速度和析出数量显著增加,粒径减小,因而对基体的强化效果更显著。同时NbC粒子产生的弹性应力场也有助于应力诱发ε马氏体转变的可逆性。更多还原

【Abstract】 In order to obtain high recovery strain in FeMnSiCrNi based shape memory alloys without training, the effects of ageing without and with pre-deformation on the shape memory effect in Fe16.78Mn5.5Si8.23Cr4.77Ni0.48Nb alloy have been studied, and the microstructure has also been studied through SEM. The results show that the shape memory effect can be improved through the ageing and 10% pre-deformation more markedly than the ageing without pre-deformation. The defects induced by deformation can be used as the nucleation sites for the NbC precipitates with faster speed and bigger amount and smaller size of NbC. The strengthening matrix effect is more remarkable as compared with ageing without pre-deformation. At the same time, the reversibility of ε martensite transformation by stress can be induced by the elastic strain field of NbC precipitates.更多还原