Microstructure evolution and dynamic recrystallization mechanisms of 316L stainless steel during hot deformation

Through isothermal compression testing at various temperatures and strain rates, the thermal deformation behavior of 316L stainless steel was investigated. Utilizing corrected true stress–strain data, an Arrhenius constitutive model with strain compensation was developed. Electron backscatter diffraction and transmission electron microscopy were employed to study the microstructure of the compressed specimens, revealing substantial impacts of temperature and strain rate. Higher temperatures boosted the transition from low-angle to high-angle grain boundaries (HAGB), while also increasing the volume percentage of dynamic recrystallization (DRX) and grain size. The impacts of Dynamic Grain Growth/Dynamic Abnormal Grain Growth restricted DRX at higher deformation temperatures and lower strain rates, but at lower temperatures, HAGB reduced with increasing strain rate. As a result, the proportion of HAGB and the volume fraction of recrystallization both decreased. The percentage of ∑3 n (1 ≤ n ≤ 3) twin boundaries also rose with temperature and followed a similar pattern to HAGB with strain rate. High temperature and high strain rate were the ideal formation conditions. Discontinuous dynamic recrystallization (DDRX) was the predominant DRX mechanism in the steel during thermal deformation, with continuous dynamic recrystallization (CDRX) acting as an auxiliary mechanism largely occurring in the low-temperature and high-strain-rate processing conditions like 1273–1323 K, 0.1–1 s −1 . Additionally, when the temperature rose, CDRX was suppressed while DDRX was encouraged. Graphical Abstract