The hot deformation behavior of a L1₂ precipitation strengthened face centered cubic high entropy alloy

In this work, the hot compressive deformation behavior of a homogenized Ni₄₅Co₁₅Cr₁₅Fe₁₅Al₈Ti₂ high entropy alloy was investigated at deformation temperatures of 900–1200°C and strain rates of 10⁻³-1 s⁻¹. Initially, combined the true stress-strain curves and hyperbolic sine function model, the constitutive equation for the flow stress of the alloy during the hot deformation process was established. Additionally, the hot processing map of the alloy at a true strain of ε = 0.5 was plotted based on the DMM model. Coupled with microstructural observations, the optimal hot processing parameters for the alloy were determined to be T = 1070–1200 °C and ε̇= 0.001–0.05 s⁻¹. Finally, the deformed microstructure of the alloy under different temperatures and strain rates was characterized using EBSD, and the dynamic recrystallization mechanisms was revealed. The flow stress decreases with the increasing deformation temperature and decreasing strain rate. As the deformation temperature increases from 900°C to 1200°C, the dynamic recrystallization mechanism transitions from continuous dynamic recrystallization (CDRX) to discontinuous dynamic recrystallization (DDRX). The findings of this study will provide valuable guidance for the development of hot forging parameters of the L1₂ strengthened FCC high-entropy alloys.