High‐Temperature Deformation Behavior and Microstructural Evolution of N06625 Nickel‐Based Alloy

Abstract

Herein, the hot deformation behavior and microstructure evolution of N06625 superalloy are studied. Hot deformation behavior at 950–1200 °C and strain rate 0.1–10 s−1 are carried out by Gleeble‐3800 thermal simulator machine. The activation energy (Q) of the alloy is calculated by the change of stress–strain curve. The microstructure of the experimental material is characterized by electron backscatter diffraction, and it is found that the recrystallization fraction rate increases with the increase of temperature, but decreases first and then increases with the increase of strain rate. Discontinuous dynamic recrystallization is the main nucleation mechanism of N06625 superalloy. Continuous dynamic recrystallization (CDRX) is the auxiliary nucleation mechanism; CDRX gradually decreases with the increase of temperature. In addition, it is found that the evolution of special boundaries is closely related to the strain rate. The longer deformation time is beneficial to the interaction of grain boundaries, which leads to the special boundary fraction, and the increase of special boundary fraction can effectively weaken the preferred orientation caused by recrystallization growth.