Study On The Long Time Structural Stability Of GH80A And GH105 Superalloys

The long time structural stability of GH80A and GH105 superalloys is investigated in this paper by means of microscope, SEM, TEM, EDS and phase extraction techniques. And the thermo-dynamic states of GH80A and GH105 are calculated by Thermo-Calc software. It is the objective of this work to characterize the microstructural and mechanical relationship. Strengthening mechanism and embrittling mechanism are also discussed in this paper.The results of GH80A superalloy studies show that after thermal exposure for 1000 hours at 700癈, the ?' and carbides coarsened, the amount of carbides increased, no TCP phase precipitated, and their microstructures and properties were stable. But after thermal exposure at 850癈, the size of y' and carbides coarsened, and the properties decreased with the prolong aged time.After thermal exposure for 1000 hours at 850癈 of GH105 superalloy, the size of y' and carbides grew, the amount of y'decreased, and plastic decreased, but rupture lifetime was stable.Using Thermal-Calc software and Ni-base database for GH80A and GH105 superalloys, the relation of the amount of precipitation phase and temperature, and the chemical composition of the precipitated phase are studied. The influence of the amount (wt%) of C, Al and Ti of alloys on the precipitation behavior of phases is also studied in the paper.