The dependence of microstructures and mechanical properties on tempering temperature (from 180 to 650 °C) in a designed 3Mn-Si-Ni martensitic steel was systematically analyzed. Microstructure was characterized using scanning and transmission electron microscopy; mechanical properties were measured using uniaxial tensile test and Charpy V-notch impact test. After tempering at different temperatures, recovery, partial recrystallization, carbides precipitation and decomposition of residual austenite were observed. After tempering at 230 °C, an excellent combination of strength (1550 MPa) and toughness (91.5 J) was achieved, due to high dislocation density and ε-carbides precipitation. However, with an increase in tempering temperature from 320 to 550 °C, tempered martensite embrittlement was observed, where impact energy was ~ 10 J. It was ascribed to cementite formation instead of transition carbides and decomposition of residual austenite. With an increase in tempering temperature up to 650 °C, high fracture impact toughness of 75 J was obtained with deteriorated tensile strength of 850 MPa due to strong recovery and partial recrystallization.

系统地分析了设计的3Mn-Si-Ni马氏体钢的组织和力学性能对回火温度（180至650℃）的依赖性。显微结构用扫描和透射电子显微镜表征。机械性能使用单轴拉伸试验和夏比V型缺口冲击试验进行测量。在不同温度下回火后，观察到恢复，部分再结晶，碳化物沉淀和残余奥氏体分解。在230°C下回火后，由于高位错密度和ε碳化物沉淀，获得了强度（1550 MPa）和韧性（91.5 J）的出色组合。然而，随着回火温度从320升高到550°C，观察到回火马氏体脆化，冲击能量约为10J。这归因于渗碳体的形成，而不是过渡碳化物和残余奥氏体的分解。随着回火温度提高到650°C，由于强的恢复和部分重结晶，获得了75 J的高断裂冲击韧性，同时使850 MPa的拉伸强度下降。