TWIP钢拉伸变形过程中微观组织的原位观察  

In-situ Observation of Microstructure in TWIP Steel During Tensile Deformation

作　　者：江海涛[1] 米振莉[1] 唐荻[1] 王海全[1] 代永娟[1] 

机构地区：[1]北京科技大学高效轧制国家工程中心

出　　处：《材料工程》2008年第1期38-41,共4页Journal of Materials Engineering

基　　金：国家自然科学基金资助项目(50575022)

摘　　要：采用扫描电镜对TWIP钢的拉伸过程进行了原位观察,研究结果表明:在TWIP钢的拉伸过程中,具有孪晶界的晶粒内部首先发生变形,并产生一定程度的加工硬化;随后其余部分晶粒发生转变,形成对变形有利的取向,从而变形得到扩展,最终得到非常大的无颈缩延伸。拉伸过程中,微裂纹首先在夹杂物和晶界处萌生,并在应力集中的作用下发生扩展连接,最终完成断裂过程。TWIP钢在变形过程中产生了大量的应变条痕,其大部分为滑移线,小部分为形变孪晶。由于孪晶诱导塑性效应,孪晶晶粒发生扭折并形成了台阶状结构,从而导致了试样表面的"褶皱"现象。The microstructure of Twinning Induced Plastic （TWIP） steel during tensile deformation was investigated with in-situ SEM observation. The results showed that the grains with twins started to deform and work harden, which lead to other grains formed favorable orientation in order to complete further deformation. This deformation mechanism of twinning induced plastic provided the specimens excellent elongation with no-necking phenomenon. In addition, microcracks generated at inclusions and grain boundaries, and merged to crack at the condition of stress concentration. A large amount of strain marks were observed in the tension specimens of the TWIP steel. The strain marks consist of slip lines and small mechanical twins. Because the kink bands and stepped structures appeared in grains for twinning induced plastic, the folding phenomenon of specimen surface occurred.

关 键 词：TWIP钢 拉伸 原位观察 微观组织 孪晶 

分 类 号：TG333.7[金属学及工艺—金属压力加工]