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T91钢经700℃时效50、100、300、500、850和1700 h后,进行SEM分析、EDS分析、析出相复型萃取TEM分析和力学性能测试分析,研究其组织性能随时间的变化规律,结果表明,随着时效时间的增加,析出相颗粒数量先增加后减少,时效850 h时达到最大,遵循N=9109+22.8t-0.02t~2关系;析出相颗粒尺寸一直增加,遵循D=0.53+5.86×10~(-4)t-1.06×10~(-7)t~2关系;析出相颗粒的面积总量一直增加,遵循S=6.5-5.0×e~((12.7-t)/504.1)关系;随时效时间的增加,基体中的Cr、Mo一直在向析出相中转移,进行合金元素再分配,在时效850 h有Laves相析出;随着时效时间的增加,强度、塑性指标总体呈下降趋势,在时效500 h时强度指标出现低值与晶粒长大和晶界弱化有关。时效产生的组织转变,使力学性能呈下降趋势。
T91 steel was aged at 700 ℃ for 50, 100, 300, 500, 850 and 1700 h, then analyzed by SEM, EDS analysis, TEM analysis and mechanical property analysis of precipitated phase compound extraction, The results show that with the increase of aging time, the number of precipitated phase particles increases first and then decreases, reaches the maximum at 850 h, and follows the relation of N = 9109 + 22.8t-0.02t ~ 2; 0.53 + 5.86 × 10 -4 t -1.66 × 10 -7 t -2. The total area of the precipitated phase particles increased continuously, and the total area of precipitated phase particles increased with S = 6.5-5.0 × e ~ ((12.7-t) /504.1). With the increase of aging time, the Cr and Mo in the matrix have been transferred to the precipitates, the redistribution of the alloying elements, Laves phase precipitation at 850 h aging; With the aging time increases, the strength and ductility The overall index showed a downward trend. The low value of the strength index at 500 h after aging was related to grain growth and grain boundary weakening. Aging caused by organizational changes, the mechanical properties showed a downward trend.