本课题面向石油化工等能源工业领域，针对高温环境下集气管材料的高温损伤机理与设计准则开展研究。采用蠕变多试样法，探究温度、时间和应力等多因素作用下材料微观组织演化及晶界孔洞化规律，提出材料的时间-温度-转变（TTT）曲线，建立虑及G相致损作用的孔洞长大模型，揭示材料的物理损伤机制，提出基于微结构特征的材料损伤分级评价方法；在多轴蠕变试验基础上，通过考虑G相析出对蠕变损伤的影响，构建新的与损伤耦合的多轴蠕变本构模型，实现对结构内部蠕变损伤演化规律的科学描述，提出高温结构的蠕变设计准则。本项目研究内容体现了力学、物理学、化学和材料等多学科领域的交叉，可望阐明服役环境下材料的损伤机理及损伤演化的基本规律，提出结构蠕变强度设计准则，为提升我国现代流程工业重大装备水平和保障我国高参数蒸汽转化装置的长周期安全运行提供支持。

Oriented to the petrochemical and other energy industries, damage mechanism and design concept of the manifold component will be investigated. Influence of complex factors such as temperature, time and stress on the microstructure evolution and the nucleation, growth and coalescence behavior of the steel will be discussed using creep multi-sample test，and time–temperature–transformation (TTT) curve of the steel will be obtained. After developing a new cavity growth model considering the effect of G-phase, the physical damage mechanism of the material and the damage classification evaluation method will be proposed. Based on the notch creep test, multiaxial creep constitutive model considering the effect of G-phase on creep damage will be established in order to analyze creep damage evolution of the manifold component. Then, the creep design criterion of the high-temperature component is proposed consequently. The contents of this proposal reflect the intersection of mechanics，physics, chemistry and material science. It is expected to clarify the damage mechanism and the basic rules of damage evolution of the material in service environment, and propose creep design criteria for the engineering structure. It is also believe to provide important support for improving the significant equipment level in the advanced process manufacturing industry and ensuring the long-term safe and reliable operation of steam reformer furnace.