在双相钢( 铁素体+马氏体，DP) 的基础上通过合理的热处理工艺得到一定量的残留奥氏体，达到强度和塑性的良好结合． 通过光学显微镜分析、X 射线衍射分析和背散射电子衍射分析等方法研究了该DP 钢的微观组织，并进一步分析了残留奥氏体随形变量的演变规律． 结果表明:残留奥氏体晶粒细小，主要呈粒状，均匀地分布在铁素体或马氏体的晶界位置，也有少量分布在铁素体内部; 残留奥氏体的转变主要集中在形变量小于10%之前，之后的转变与应变成线性关系，拉伸断裂后未发现残留奥氏体．

A certain amount of retained austenite in the dual phase steel was obtained through a rational heat treatmentprocess,and the steel thus achieved a good combination of strength and plasticity.Then,the microstructure ofthe DP steel was investigated by means of the optical metallography,XRD and the electron back-scatter diffraction( EBSD),and the evolution rules of the retained austenite during the deformation were discussed.The results showthat ( 1) the retained austenite is fine and mainly granular,and most of it distributes uniformly at the boundaries offerrites and /or martensites with few in the ferrites; ( 2) the transformation of retained austenite mainly occurs at thedeformation extent of less than10%,and it is linearly related to strain at the deformation extent of more than 10%;and ( 3) in the EBSD observation,the retained austenite is not found in the fractured sample after tensile fracture.