In this contribution, a series of isothermal compression tests for the 825 nickel-based alloy were performed using a Gleeble-3800 computer-controlled thermomechanical simulator at the compression temperature range of 850 °C to 1150 °C and the strain rate range of 0.14 s⁻¹ to 2.72 s⁻¹. The hot deformation equation of the alloy is derived from the piecewise model based on the theory of work hardening-dynamic recovery and dynamic recrystallization (DRX), respectively. Comparisons between the predicted and experimental data indicate that the proposed constitutive model had a highly accurate prediction. The deformation rate and temperature effect were associated with microstructural change, and the evolution of the microstructure was analyzed through electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). The dislocation densities of the alloy at the deformation of 850 °C and 2.72 s⁻¹ is higher than at the other deformation, the higher dislocation density is the higher stored energy and the higher degree of DRX. As well, two types of DRX nucleation mechanisms have been identified: discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX). Changes in grain boundary have significant effect on the DRX nucleation of the alloy, twin boundaries act as potential barriers limiting dislocation slip and motion and eventually leading to the accumulation of dislocation during plastic deformation. This study identified that the major contribution which results in the growth of new twins in DRX grains is the new boundary of Σ3 twins.

A new rolling process of the 304/Q345R composite plate based on a corrugated interface was developed. Through numerical simulation and rolling experiments, the metal deformation law, the stress and strain field distribution, and the bond strength of the corrugated plate were studied. By comparison, the corrugated interface effectively increased the length of the composite interface. Also, the composite interface from the 2D corrugated surface became a 3D corrugated surface, and a combination of the 304/Q345R composite plate metallurgy was achieved with a low reduction rate. Simultaneously, the interface bonding strength was improved.

In order to study the microstructure evolution and flow stress behavior of as cast antibacterial austenitic stainless steel containing 1.52 wt.% copper, Gleeble 3800 was used for thermal compression simulation test. Through OM and EBSD analysis, it is found that the dynamic recrystallization mechanism of thermal deformation is mainly discontinuous dynamic recrystallization. With the increase of deformation temperature and deformation rate, the proportion of recrystallization nucleation gradually increases. The growth of twins relies on recrystallization and, at the same time, promotes dynamic recrystallization. Considering the influence of strain on flow stress, the strain compensation Arrhenius model is established according to the obtained stress-strain curve, and high accuracy is obtained. The correlation coefficient and average relative absolute error are 0.979 and 7.066% respectively. These results provide basic guidance for the technology of microstructure control and excellent mechanical properties of antibacterial stainless steel.