【摘要】 为研究T91钢在高温及应力共同作用下的老化行为,对T91钢在800℃、0~36 MPa应力条件下时效过程中组织和性能的演化进行了研究。结果表明,时效过程中回火马氏体的板条组织特征逐渐消失,晶内和晶界的碳化物数量逐渐减少但尺寸逐渐增大,时效1656 h后的晶界碳化物颗粒尺寸达到4μm。抗拉强度、屈服强度和断后伸长率都随时效时间延长而降低,时效时间达到1656 h时,其抗拉强度为580 MPa,比初始抗拉强度值降低了15%。应力显著促进了T91钢显微组织老化和性能劣化的过程。更多还原

【Abstract】 In order to investigate the degradation in microstructure and properties of T91 steel under high temperature and stress,the evolution of microstructure and properties during aging at 800 ℃ under stress of 0-36 MPa was investigated. The results indicate that the lath characteristics of the tempered martensite gradually disappears during aging. The number of precipitations in grains and at grain boundaries deceases while the size increases and the precipitation of 4 μm at grain boundaries is observed after aging for 1656 h. The tensile strength,yield strength and elongation of the steel decreases during aging. The tensile strength of the steel after aging at 800 ℃ for1656 h is 580 MPa,about 85% of that before aging. The significant effect of the stress on the degradation in microstructure and properties of the aged steel is observed.更多还原