低硅含铝TRIP钢断裂机理及其残余奥氏体的稳定性

摘要

TRIP钢在原位拉伸过程中应力迫使残余奥氏体向马氏体转变,在此过程中伴随着应力松弛,断裂被延迟.整个变形过程中,试样加载后,先在铁素体内部产生滑移带,滑移带的方向与拉应力的方向约成45°;TRIP钢裂纹源首先在V型缺口与夹杂物处产生,然后扩展并连接,且裂纹的走向经常产生转折,即残余奥氏体转变为马氏体裂纹的尖端被钝化.利用EBSD技术,分析了未变形与断裂后钢板残余奥氏体的分布与稳定性,发现小尺寸和分布在铁素体内部的残余奥氏体比较稳定.%Stress compels residual austenite to martensite transformation of TRIP steel in situ-tensile course, fracture is delayed with stress relaxation.Take a general view of the whole deformation process, first of all, interior of loading sample gives birth to slip band, its' heading is about 45°angle along with tensile stress.And the crack initiation primarily comes into being at the point of impurity and V shape nick, subsequently, spread and join, the trend of crack often generates turn, namely residual austenite translates martensite, the tip of crack is passivation.EBSD technique is utilized, distribution and stability of residual austenite for not deformative and broken sheets are analyzed, mini-size and ferrite interior residual austenite are discovered relatively stable.