Quantitative analysis of carbides and the sigma phase in thermally exposed GTD-111

The effects of thermal exposure on gamma', carbides and TCP-type phases, such as the sigma and eta phases, in the nickel-based superalloy GTD-111 were investigated in this study. The thermal exposure was performed at 871 degrees C and 982 degrees C for 1,000, 5,000 and 10,000 h, after which the thermally exposed specimens were compared in terms of their microstructure, weight fraction and growth rate of each precipitate. Electrolytic extraction and Rietveld refinement were successfully applied for a quantitative analysis of the carbides and the sigma phase in the thermally exposed GTD-111. The weight fractions of MC, Cr-rich M23C6 and the sigma phase for various thermal exposure times and temperatures were obtained to understand the formation and decomposition rate of each phase.