Coarsening behavior of γ′ precipitates in laser solid forming rene88dt superalloy during high temperature treatment

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°C) 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 γ matrix.