Ni_2MnGa铁磁形状记忆合金开裂的原位研究  

IN SITU STUDY OF CRACKING FOR Ni_2MnGa FERROMAGNETIC SHAPE MEMORY ALLOY

作　　者：沈连成[1] 何健英[1] 宿彦京[1] 褚武扬[1] 乔利杰[1] 

机构地区：[1]北京科技大学材料物理系,北京100083

出　　处：《金属学报》2006年第8期810-814,共5页Acta Metallurgica Sinica

基　　金：国家自然科学基金50428101

摘　　要：对Ni_2MnGa铁磁形状记忆合金的缺口试样,通过在微分干涉相衬显微镜下原位拉伸,研究了裂纹形核、扩展和马氏体相变以及塑性变形的关系．结果表明,拉伸时首先形成马氏体,当裂尖应力集中足够大时就会在裂尖产生局部塑性区,微裂纹易于沿马氏体界面形核,但也可在塑性区中形核．随载荷升高,微裂纹沿马氏体不连续形核,通过韧带剪切连接,从而导致裂纹扩展阻力也随裂纹扩展而增大．The relationship between crack nucleation, martensitic transformation and plastic deformation of Ni2MnGa ferromagnetic shape memory alloy has been studied in situ using a differential interference contrast （DIC） microscopy. The result showed that martensites formed first during loading and then a plastic zone appeared when the stress was increased further. Microcrack initiated preferentially along the interface of martensite, but also initiated in the plastic zone . With increasing the load, microcracks initiated discontinuously along the martensites and connected through shear fracture of the ligaments.

关 键 词：NI2MNGA 原位拉伸 马氏体 裂纹形核 

分 类 号：TG115.2[金属学及工艺—物理冶金] TG139[金属学及工艺—金属学]