双相不锈钢以其优异的高温力学性能、耐腐蚀性和抗辐照损伤性能,在核电站等领域应用广泛.在300～550 ℃范围内服役时,合金中的铁素体相发生分解,形成体心结构的富Fe相和富Cr相,使双相不锈钢的力学性能变差,引起“475℃脆性”,影响合金的使用寿命和安全性.然而,Fe-Cr合金的分解机制随成分的变化以及混溶隙边界仍不明确,而分解机制和相边界决定着合金的分解动力学和微观组织.综述了近年来实验和相场模拟对Fe-Cr合金相分解的研究结果,并对需要解决的问题和发展方向进行了论述,以期为Fe-Cr系合金相分解研究提供参考.%Duplex stainless steel has been used widely in industrial fields,such as nuclear power plant,for its excellent mechanical property,corrosion resistance and resistance to irradiation damage at high temperature.The ferritic phase decomposes into iron-rich phase and chromium-rich phase in the range of 300—550 ℃,which results in the "475 ℃ embrittlement" and the poor mechanical properties,affecting the service life and safety of duplex stainless steel.However,the decomposition mechanism of the alloy with the composition variation,and the boundary of miscible gap arc still unclear,which affects the decomposition kinetics and microstructure of the alloy.The paper reviews the results of experiments and phase-field simulations on the phase decomposition of Fe-Cr alloys,discusses the unresolved issues and development direction in this field,attempting to provide a reference for related studies.
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