Study on Thermal Deformation Constitutive Model and Microstructure of Forged N06625 Nickel-Based Alloy

A single-pass compression experiment was conducted to investigate the thermal deformation behavior of the N06625 nickel-based alloy at temperatures ranging from 950 to 1200 °C, strain rates of 0.1 to 10 s⁻¹, and a deformation of 60%. The flow stress initially increases to a peak value during work hardening, subsequently decreases due to dynamic softening, and ultimately stabilizes. Based on the resulting stress-strain curves, three constitutive models were established: the strain-compensated Arrhenius (SCA) model, the BP artificial neural network (BP) model, and the piecewise function (PF) model. Among these, the BP model provided the most accurate description of the material’s behavior. Power dissipation maps and processing maps were constructed at different strain levels. The results indicate that the optimal thermal processing window lies between 1100 and 1200 °C, with a strain rate below 0.37 s⁻¹. Dynamic recrystallization (DRX) plays a significant role in determining the power dissipation efficiency (η), with greater DRX leading to higher dissipation values. Finally, a dynamic recrystallization kinetics model was developed to provide a basis for further implementation in finite element simulations.