Fe20Cr9Ni铸造奥氏体不锈钢中σ相的析出动力学  

Kinetics ofσphase precipitation in a Fe20Cr9Ni cast austenite stainless steel

作　　者：王永强[1] 孙立[2] 李娜[2] 林苏华[2] 杨滨[3] 

机构地区：[1]安徽工业大学材料科学与工程学院,安徽马鞍山243002 [2]安徽工业大学冶金工程学院,安徽马鞍山243002 [3]北京科技大学新金属材料国家重点实验室,北京100083

出　　处：《钢铁研究学报》2016年第7期67-73,共7页Journal of Iron and Steel Research

基　　金：安徽省自然科学基金资助项目(1508085QE102)

摘　　要：采用EPMA、XRD、TEM等手段分析了压水堆核电站主管道用Fe20Cr9Ni铸造奥氏体不锈钢中σ相的成分和结构,通过等温时效处理、金相组织分析,研究了σ相析出动力学,获得了σ相析出的时间-温度-转变（TTT）曲线及JMA析出动力学方程。研究结果表明：Fe20Cr9Ni中σ相析出的温度范围为600~840℃,750℃时σ相析出动力学最快,600~750℃时σ相的析出量计算值与实验值符合得较好。σ相形成激活能为149kJ/mol,接近Cr在铁素体中的扩散激活能值,其过程主要受Cr扩散控制。Fe20Cr9Ni铸造奥氏体不锈钢中σ相析出特征主要由其特殊的合金成分和组织结构决定。The composition and structure ofσphase in a Fe20Cr9 Ni cast austenite stainless steel（CASS）which had been widely used in primary coolant pipes of nuclear power plants,were detected by EPMA,XRD and TEM technologies.The kinetics ofσphase precipitation in Fe20Cr9 Ni CASS was investigated by the method of isothermal aging treatment and metallographic microstructures analysis.The time-temperature-transformation diagram for theσphase was got and a model to predict the kinetics ofσphase formation using a Johnson-Mehl-Avrami（JMA）type expression was proposed too.The results show that the precipitation temperature region of theσphase is from 600 to 840℃and the higher kinetics ofσphase formation occurs at 750℃.The activation energy forσphase formation in Fe20Cr9 Ni CASS is 149kJ/mol,that is approximatively equivalent to the value of activation energy for Cr diffusion in ferrite,indicating that Cr diffusion is probably the major governing factor of theσphase precipitation process.The mechanism ofσphase precipitation in Fe20Cr9 Ni CASS is determined by the special alloy composition and structure.

关 键 词：Fe20Cr9Ni铸造奥氏体不锈钢 Σ相 析出动力学 激活能 

分 类 号：TG142.71[一般工业技术—材料科学与工程]