It has been proven that martensite matrix accompanied by fine reversed austenite is beneficial to improve the strength and toughness in martensitic steels to a certain extent. In order to achieve this unique microstructure, the existing methods, like quenching at high temperatures, multiple heat treatment processes, increasing Ni content, raise the economic cost and operation difficulty. In this work, fine reversed austenite was formed in Fe13Cr4NiMo steel with relatively low nickel content (4 wt%) by one-time relatively low temperature quenching (860 °C) and tempering process. Then the formation mechanism and effect on mechanical properties of reversed austenite were discussed. The 0.55 vol% reversed austenite with the size of 260 nm can be formed in Fe13Cr4NiMo steel under quenching at 860 °C for 40 min and tempering at 650 °C for 2 h. The reversed austenite maintained a deviation of ∼2° from K-S relationship with the martensite matrix. In addition, the formation of reversed austenite was caused by short circuit diffusion of element-free redistribution, which caused the reversed austenite to be more inclined to nucleate at subgrain boundaries and grow up restrictedly. Furthermore, the Fe13Cr4NiMo steel that contained reversed austenite hindering dislocation movement and coordinating deformation possessed excellent plasticity of 18.4 % and Charpy impact energy of 289 J while maintaining high strength of 872 MPa at room temperature.

中文翻译：

---

通过反转奥氏体提高超低碳马氏体不锈钢的强度和韧性

实践证明，马氏体基体中伴有细小的反转奥氏体，在一定程度上有利于提高马氏体钢的强度和韧性。为了实现这种独特的显微组织，现有的方法如高温淬火、多重热处理工艺、增加Ni含量等，增加了经济成本和操作难度。在这项工作中，通过一次性相对低温淬火（860 ℃）和回火工艺，在镍含量相对较低（4 wt%）的 Fe13Cr4NiMo 钢中形成了细小的反转奥氏体。然后讨论了反转奥氏体的形成机制及其对力学性能的影响。Fe13Cr4NiMo钢在860℃淬火40min、650℃回火2h后可形成0.55vol%、尺寸为260nm的反转奥氏体。反转奥氏体与马氏体基体的 KS 关系保持约 2° 的偏差。此外，反转奥氏体的形成是由无元素再分布的短路扩散引起的，这导致反转奥氏体更倾向于在亚晶界形核并受限地长大。此外，含有阻碍位错运动和协调变形的反转奥氏体的Fe13Cr4NiMo钢具有18.4%的优异塑性和289 J的夏比冲击功，同时在室温下保持872 MPa的高强度。