Solidification of a nickel-based superalloy containing copper: A study combined with experiment and phase-field simulation

Abstract

This work systematically investigates the influence of the Cu element on the solidification characteristics of GH4061, a novel burning-resistant nickel-based superalloy, through the combination of experimental characterization and phase-field simulation, along with an exploration of the underlying mechanisms. It has been revealed that with the Cu content increasing, the as-cast grain size, secondary dendrite arm spacing, and the volume fraction and size of primary carbides in the alloy initially increased before subsequently decreasing. Moreover, the morphology of primary carbides will also transform from a long strip to a block structure. These phenomena observed can be elucidated by the interaction among the competitive dynamics of matrix phase grain nucleation and growth, the solid-liquid interface energy and solute element diffusion, as well as the segregation of carbide-forming elements and the overall solidification path. The findings of this work will contribute to the design and fabrication of new high-temperature structural materials that exhibit improved burning resistance through the further optimization of alloy composition.