形状记忆合金中的马氏体变体在外场下的再取向和再分布机制(英文)

Mechanism of Reorientation and Redistribution of Multi-Variants in Shape Memory Alloys under External Field

利用相场方法研究了马氏体变体在循环应力作用下再取向和再分布的微观机制。模拟结果表明,随着外应力的增加,在孪晶界面会出现母相的形核和长大,以此实现变体间的转化,这是3种变体转化为2种变体的主要再取向机制;卸载后消失的变体在孪晶界面重新形核并长大以完成系统内微观组织的再分布。在Mn-Cu合金中这种机制是控制循环载荷下形状记忆效应产生的主要机制。

The mechanism of reorientation and redistribution of martensitic multi-variants under the cyclic stress was studied by using Phase-Field method. The results showed that under the small loading, the twin boundary migration is the main mechanism and three variants can be kept in the system, with the increase of external stress, the nucleation and growth of parent at the twin interface is the main mechanism to realize the reorientation of 3---＊2 variants. After removing the loading, the vanished variant nucleates at the twin boundary to perform the redistribution of inner microstructure in the system. This kind of mechanism controls the shape memory effect of the Mn-Cu alloy during the cyclic loading.