Dependence of composition of γ′/γ phases on aging time and temperature in superalloy GH742

The phase composition of γ′ phase and γ matrix in GH742 was investigated by energy dispersive of X-ray spectroscopy (EDX) in an analysis transmission electron microscope (TEM-EDX). The dependence of composition of γ′ and γ phase on aging time indicates that the composition of γ′ and γ phase evolves drastically in short aging time at the temperature of 1050°C and reaches the equilibrium condition when aging for 1440 min. The dependence of composition of γ′ and γ phase on temperature indicates that the composition of γ′ and γ phases evolves with the increasing temperature in the range of 750°C to 1100°C. The dependence of partitioning ratios C_γ′/C_γ on temperature shows that the partitioning ratios C_γ′/C_γ of γ′-forming elements Ti, Al, Nb, Ni have a decrease and those of γ-forming elements Cr, Co, Mo have an increase with the temperature increasing.