含铌低硅TRIP钢的拉伸行为研究

Study on Tensile Behavior of Low Silicon TRIP Steel Containing Niobium

采用定量拉伸、彩色金相、SEM、TEM和XRD对含铌低硅TRIP钢拉伸过程中的相变和应变硬化行为进行了研究。结果表明:在单向拉伸过程中,残余奥氏体的稳步相变使得塑性增加。残余奥氏体的相变速率与真应变的关系可以用ln[(Vγ0-Vγ)/(Vγ0-Vγu)]=lnk-cε来表示,随应变的进行,c值减小,残余奥氏体的稳定性增加。在均匀塑性变形阶段,TRIP钢的瞬时应变硬化指数n*值随真应变ε的变化与残余奥氏体向马氏体相变量有关。

By means of quantitative tension,tint-etched metallograph,SEM,TEM and XRD techniques,the tensile properties,transformation behavior and strain hardening behavior during tensile straining of low silicon TRIP steel containing niobium were investigated.The results indicated that metastable austenite stably transforms during straining,bringing about increase of plasticity.The relationship between the transformation rate of retained austenite and true strain in uniaxial tensile test can be expressed as ln[（Vγ0-Vγ）/（Vγ0-Vγu）]=lnk-cε.As the strain increases,the c value,which is determined by the transformation rate decreases,and the stability of retained austenite is strengthened.During uniform plastic deformation,variation of instantaneous strain hardening n＊ value versus true strain ε has a relation with the martensitic transformation volume fraction of retained austenite.