【摘要】 对新开发马氏体不锈钢4Cr13Cu在不同冷速下的过冷奥氏体连续冷却转变行为和等温转变动力学行为进行了研究，采用DIL805A高精度差分热膨胀仪测量4Cr13Cu钢线膨胀行为，利用光学显微镜(OM)和扫描电镜(SEM)分析冷却转变产物；根据JMA公式计算4Cr13Cu钢珠光体等温相变激活能和Avrami指数。研究结果表明，4Cr13Cu钢过冷奥氏体连续冷却过程中，当冷速不低于0.1℃/s时，转变产物为全马氏体组织；当冷速小于0.1℃/s时，转变产物为马氏体和珠光体的混合组织，且随着冷速的降低珠光体组织含量增加。4Cr13Cu钢的珠光体等温转变区间为600～680℃,鼻尖转变温度约为635℃,不同等温条件下的JMA方程计算值与实测值匹配度较好。珠光体转变激活能约为93.1 kJ/mol, Avrami指数n在1.5～2.5范围内，珠光体形核速率随着等温时间延长而降低。更多还原

【Abstract】 Continuous cooling transformation behavior and isothermal transformation kinetics of undercooled austenite of a newly developed martensitic stainless steel 4Cr13Cu at different cooling rates were studied. The linear expansion behavior of the 4Cr13Cu steel was measured by DIL805A high-precision differential thermal dilatometer, and the cooling transformation products were analyzed by OM and SEM. According to the JMA formula, the activation energy and Avrami index of pearlite isothermal phase transformation in 4Cr13Cu steel were calculated. The results show that during the continuous cooling process of undercooled austenite of the 4Cr13Cu steel, when the cooling rate is greater than 0.1 ℃/s, the transformation product is full martensite. When the cooling rate is less than 0.1 ℃/s, the transformation product is a mixture of martensite and pearlite, and the content of pearlite increases with the decrease of cooling rate. The isothermal transformation range of pearlite in the 4Cr13Cu steel is 600-680 ℃, and the nose transformation temperature is about 635 ℃. The calculated values of JMA equations under different isothermal conditions are in good agreement with the measured values. The activation energy of pearlite transformation is about 93.1 kJ/mol, and the Avrami index n is in the range of 1.5-2.5, the nucleation rate of pearlite decreases with the prolongation of isothermal time.更多还原