Effect of different processing technologies and heat treatments on the microstructure and creep behavior of GH4169 superalloy

By the measurement of creep property and microstructure observation, the influence of different processing technologies and different heat treatments on the creep property of GH4169 superalloy has been investigated. It was found that the processing technologies of GH4169 superalloy can considerably affect the creep life. As compared to the hot continuous rolled alloy after standard heat treatment (abbreviated as HCR-ST), the radial forged alloy after the same treatment (abbreviated as RF-ST) precipitated more δ phase and led to shorter creep life. Besides, different heat treatments also resulted in different creep properties. Two specimens, both were taken from the hot continuous rolled alloy, were exposed to standard heat treatment (ST) and direct-aged treatment (DA), respectively. They are abbreviated as HCR-ST and HCR-DA. The results indicate that the HCR-DA specimen with clean grain boundaries and with no δ precipitates on them obtained much longer creep life. Without δ phase, the stress rupture life of the HCR-DA specimen is double of the RF-ST specimen whose amount of δ phase was largest.