火力发电厂高压加热器管承受高温、高压水蒸汽的氧化和应力而造成的泄露是高压加热器停运最主要的原因。本项目以高压加热器用TP439铁素体不锈钢为研究对象，研究高温水蒸汽耦合应力材料的氧化和失效行为。通过改变应力加载方式、速率和大小等因素探明应力作用下的氧化动力学规律；通过研究应力对氧化膜中离子扩散的影响，阐明应力在氧化膜形成和演变过程中的作用机制。研究基体中晶界元素分布、晶粒中位错的分布的演化，阐明应力对晶界扩散和氧化行为的影响，找出高温水蒸汽与应力耦合作用下材料失效的关键因素，阐明高材料加速失效机理，建立高温水蒸汽环境中力学-化学协同作用下的氧化模型，并提出失效判据。课题的研究可深入认识高温、高压水蒸汽环境下材料失效机理，有助于TP439不锈钢结构件在服役条件下的风险评估及寿命预测。

High-pressure heater tubes of thermal power plants are suffered from stress and oxidation resulted from high-pressure and high temperature water vapor，which is the main reason for heater tube leakage and high pressure heater shutdown. The main aim of the present project is to study oxidation and failure behavior of TP439 ferritic stainless steel under the high temperature water vapor coupled stress, which used for high pressure heater. The oxidation kinetics will be obtained by changing the stress loading mode, rate and magnitude. The mechanism and effect of stress in the formation and evolution of oxide film will be clarified by studying the effect of stress on ion diffusion in oxide film. The effect of stress on grain boundary diffusion and oxidation behavior will be investigated by studying evolution of grain boundary element distribution in the matrix and distribution of dislocations in the grain. TP439 failure criterion will be proposed by analyzing the key factors of material failure under high temperature steam and stress. The synergy of mechanics and chemistry model will be established under the high temperature water vapor environment. The research of this subject can help us understand the mechanism of material failure under high temperature and high pressure water vapor environment. Furthermore, it is helpful to risk assessment and life prediction of TP439 stainless steel structural parts under service conditions.