A Study on the Hot Deformation and Recrystallization Behavior of a Novel Ni-Fe-Cr Superalloy at Ultra-Supercritical Conditions

Abstract

AbstactThis study presents an in-depth investigation of the hot deformation behavior and microstructural evolution of a novel Ni-Fe-Cr superalloy, with the aim of optimizing its hot working process. Hot compression tests were conducted using a Gleeble-3500 thermal simulator across a range of temperatures (1000-1200°C) and strain rates (0.01-10 s⁻¹). It reveals that the alloy's flow stress decreases with increasing temperature and decreasing strain rate. Furthermore, an Arrhenius constitutive model was developed and refined using a six-term polynomial correction, providing a more accurate description of the alloy's hot working performance. The establishment of the hot working map reveals that the optimal processing window is 1000~1200°C with a strain rate of 0.1/s. It is found that dynamic recrystallization (DRX), primarily continuous dynamic recrystallization (DDRX) with supplementary continuous dynamic recrystallization (CDRX), governs the softening mechanism. Grain uniformity and recrystallization degree increased with deformation temperature. These findings offer valuable insights for optimizing the hot working process of the Ni-Fe-Cr superalloy, facilitating its high-performance applications.

Keywords: Ni-Fe-Cr superalloy, hot deformation behavior, microstructural evolution, dynamic recrystallization (DRX), hot processing map