摘要
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。
Evolutions of microstructure and shape memory effect of a Fe-14Mn-5.5Si-8Cr-5Ni alloy with thermal cycling were investigated by OM observation and resistivity measurement. The results show that the shape recovery rate is markedly enhanced after one thermal cycle in the temperature range of 298 K-353 K,520 K,773 K and 77-773 K. The shape recovery rate increases by 26% and 36% after five thermal cycles of between 298-773 K and 77-773 K, respectively. The thermal cycling not only decreases remarkably the amount of thermal-induced e martensite produced by the quenching thermal stress, but also introduces lots of stacking faults resulting from the reverse transformation of thermal-induced e martensite. Compared to the solution treated alloy, the amount of ct＇ martensite after deformation decreases significantly, and the stress-induced e martensite forms in a domain manner after thermal cycling. This is the reason of the remarkable improvement of shape memory effect after thermal cycling. Because more stacking faults are introduced by the thermal cycling in the range of 77-773 K than that of 298-773 K, the shape memory effect is improved more remarkably by the thermal cycling of 77-773 K.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2012年第8期1-6,共6页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金项目(50501015
50871072)
四川省青年基金(2010A01-436)
关键词
形状记忆合金
形状记忆效应
热循环
热诱发ε马氏体
shape memory alloys
shape memory effect
thermal cycling
thermal-induced e martensite
