通过XRD、SEM、EBSD、TEM和APT等手段系统研究了一种含Cu的Fe-Cr-Co-Ni-Mo系马氏体时效不锈钢在时效过程中析出相和逆转变奥氏体的演变规律及其对力学性能的影响。结果表明，时效过程中在基体中依次析出富Cu相和富Mo相，部分富Mo相依附于富Cu相形核长大。此外，随着时效时间的延长，逆转变奥氏体的含量增加，且逆转变奥氏体中的Cu和Ni含量逐渐升高，奥氏体机械稳定性增强，韧化作用提高。试样时效90 h后，材料的屈服强度和抗拉强度分别达到1270和1495 MPa，冲击功为81 J，断裂韧性为102 MPa·m^1/2，与商用马氏体时效不锈钢相比，表现出更为优异的强韧性匹配。

An increase in strength often leads to a decrease in the ductility and toughness of maraging stainless steels; this phenomenon is known as the strength-ductility/toughness trade-off dilemma in structural materials. Some studies have found that the introduction of submicro/nanometer-sized retained or reverted austenite could mitigate the strength-ductility/toughness trade-off of high-strength maraging stainless steels. In this work, a novel strategy to accelerate austenite reversion by Cu addition in a Fe-Ni-Mo-Co-Cr maraging stainless steel was studied. In addition, the aging behavior and its effects on the mechanical properties of a Cu-containing Fe-Cr-Co-Ni-Mo maraging stainless steel were systematically studied. Transmission electron microscope characterizations showed that Cu- and Mo-rich phases precipitated from the steel matrix in sequence during the aging process; more specifically, a part of Mo-rich phase nucleated at the Cu-rich phase and then grew. Moreover, along with the segregation of Cu and Ni, reverted austenite was formed gradually. With an increase in the aging time, the stability of the reverted austenite increased, resulting in a substantial increase in its toughness. After aging for 90 h, the yield and tensile strengths of the steel reached 1270 and 1495 MPa, respectively, and the impact energy and fracture toughness were 81 J and 102 MPa·m^1/2, respectively, showing an excellent match of strength and toughness compared with commercial maraging stainless steels.