激光立体成形Rene88DT高温合金γ′相的高温粗化行为研究

Coarsening Behavior of γ′ Precipitates in Laser Solid Forming Rene88DT Superalloy during High Temperature Treatment

摘要:

采用激光立体成形技术 (LSF) 制备Rene88DT高温合金，对其在760~840 ℃温度区间进行高温短时 (4~16 h)时效处理，采用微观测试分析方法对高温短时时效处理后γ′相形态、尺寸变化及粗化动力学行为进行了研究。结果表明：激光立体成形Rene88DT高温合金在高温短时时效条件下，γ′相分布均匀，形态基本为球形，时效温度对γ′相的影响比时效时间更为显著；γ′相的粗化规律符合Lifshitz-Slyozov-Wagner (LSW) 理论，γ′粗化激活能Q=211.65 kJ/mol，γ′相的粗化行为主要由Ti和Al在基体中的扩散所控制

Abstract:

Rene88DT superalloy was prepared by laser solid forming (LSF). The morphology, size and coarsening kinetics of γ′ precipitates of LSF Rene88DT during aging treatment at high temperature (760-840 ℃) for short time (4-16 h) were studied by microscopic measurements and analysis. The results show that γ′ precipitates are evolved gradually to be spherical in morphology and uniformly distributed in the γ matrix during high temperature and short time aging treatment. It can be found that the aging temperature has more significant effect on the γ′ precipitates than the aging time. Meanwhile, the coarsening behavior of the main strengthening precipitates γ′ obeys the Lifshitz-Slyozov-Wagner (LSW) theory. The diffusion activation energy Q in coarsening of LSF Rene88DT γ′ precipitates is 211.65 kJ/mol. The coarsening behavior of γ′ precipitates is controlled by the diffusion of Al and Ti in the g matrix.