Microstructure and mechanical properties of nickel-based wrought superalloys under thermal-mechanical coupling: A review with Inconel 718, 625 as main cases

The typical processing and in-service behaviors of nickel-based wrought superalloys involve complex thermal-mechanical coupling effects, including elastic and plastic deformations, phase transformations, and other microstructural evolutions, directly impacting the mechanical properties. This review article provides an in-depth discussion on the microstructural evolution of these superalloys under thermal-mechanical coupling, focusing on two key aspects: the thermoplastic deformation behavior, and the phase transformation behavior in temperature/stress coupled field. The dynamic recrystallization (DRX) behavior during hot deformation and its improvement strategies are discussed in detail. The differences in phase precipitation behavior under conventional heat treatment and thermal-mechanical coupling conditions are compared. The mechanisms driving changes in precipitate characteristics are explored, enabling precise control of precipitates. This article further investigates the intricate relationship between the mechanical properties of nickel-based wrought superalloys and the characteristics of their precipitates, offering guidance for current and future optimizations. It also delves into the latest research advancements in precisely tailoring the precipitates through thermal-mechanical coupling methods to optimize these mechanical properties. Finally, it outlines several promising future research directions in this field.