Dynamic recrystallization behavior under steady and transient mutation deformation state

Dynamic recrystallization (DRX), which is a critical regulatory procedure in the hot rolling process, can greatly improve the microstructure of metallic materials. In recent years, the development of innovative rolling equipment technology (flexible rolling and ring rolling) has brought new challenges to the traditional DRX steady deformation state regulating procedure. In this paper, the coupled behaviors of DRX hot deformation parameters in the constant and transient mutation deformation state of metallic materials are investigated. By analyzing the flow stress curves, DRX was found to be the predominant softening mechanism. The Zener–Hollomon equation is established under a stable deformation state, coupling stress, strain rate, and deformation temperature. A new DRX model, based on the integration of different algorithms found in the literature, is proposed to predict the DRX volume fraction. These values are in good agreement with the experimental ones. Furthermore, electron backscattering diffraction (EBSD) was used to characterize the microstructural morphology under steady and transient mutation deformation state. The DRX mechanisms were understood for all of the stain rate transient mutations and for the flexible rolling dynamic deformation state as CDRX to DDRX and then to CDRX.