【摘要】 为开发免训练、高可恢复变形量的FeMnSiCrNi合金,研究了直接时效和形变时效对FeMnSiCrNiNbC合金形状记忆效应的影响,通过TEM分析了微观组织的变化。结果表明:与直接时效相比,10%室温形变后时效对合金形状记忆效应的提高更显著。形变后产生的晶体缺陷提供了NbC的形核位置,使NbC的析出速度显著增加,析出数量增多,粒径减小,因而对基体的强化效果更显著。同时NbC析出导致的弹性应变场提高了应力诱发ε马氏体逆转变的可逆性。更多还原

【Abstract】 In order to obtain high recovery strain in FeMnSiCrNi based shape memory alloys without training, the influence of ageing without and with pre-deformation on shape memory effect in an Fe16.78Mn5.5Si8.23Cr4.77Ni0.48Nb alloy have been studied, the evolution of microstructures has been studied by means of TEM. The results showed that the shape memory effect can be improved more markedly through ageing with 10% pre-deformation compared to ageing without pre-deformation. The defects induced by deformation can be as nucleation sites for NbC precipitates, which makes the precipitation of NbC more quickly and the amount of NbC much more and the size of NbC smaller, resulting in the more remarkable effect of strengthening matrix as compared with ageing without pre-deformation. At the same time, the elastic strain field of NbC precipition improved the reversibility of stress induced ε martensite.更多还原