Identification of precipitates in the as-cast microstructure and its evolution behavior during homogenization of a difficult-to-deform GH4141 superalloy

Abstract:

GH4141 wrought superalloy is widely used in the manufacture of high-temperature load-bearing components for aerospace engines due to its high strength and good oxidation resistance at high temperatures. In this paper, based on chemical composition analysis and crystallographic method, the typical precipitates in the as-cast GH4141 alloy were identified and analyzed in detail. The dissolution behaviors of the precipitates during the homogenization process were analyzed through the high-temperature homogenization experiments. Under the medium and low temperature homogenization conditions of 1130~1160 oC, the needle-like σ phase, plate shape η phase, M3B2 boride and γ’ strengthening phases of the original as-cast structure are dissolved into the matrix, while the M6C carbide can still be existed. Under the condition of high temperature homogenization at 1190~1210 oC, most of the precipitates including M6C in the alloy have been dissolved into the γ matrix, and only a small part of MC carbides remain in the structure. Besides, it’s worth noting that the MC carbides are dissolved in the solid-liquid two-phase region, and the MC carbides are difficult to be completely dissolved and eliminated through homogenization heat treatment.