Effect of high temperature aging on microstructures and tensile properties of a selective laser melted GTD222 superalloy

GTD222 is an important structural alloy that is applied as a high-temperature hot-end part. In this work, the effect of a high-temperature (800-950 degrees C) aging treatment on the microstructural evolution and mechanical performance of a GTD222 superalloy fabricated with selective laser melting (SLM) processed is investigated. Precipitates of gamma'-Ni3(Al, Ti) with different morphologies and sizes are obtained after different high-temperature aging treatment processes. When the aging temperature is below 850 degrees C, a large number of very small spherical gamma' phases and coarse plate like gamma' are precipitated in the aged samples. The spherical gamma' precipitates are homogeneously distributed in the alloy, while the plate-like gamma' precipitates are distributed along the boundaries of the cells. With increasing aging temperature, the gamma' precipitates are significantly coarsened, and the yield strength (YS) decreases. The strength and ductility reach the best balance herein when the aging temperature ranges from 850 degrees C to 900 degrees C. (C) 2020 Elsevier B.V. All rights reserved.