Research on the sensitivity behavior of special microstructural transformations during the hot deformation process of Fe₄₉Mn_33.2Cr_9.6Co_8.2 high-entropy alloy

This article performs hot compression experiments on the Fe₄₉Mn_33.2Cr_9.6Co_8.2 high-entropy alloy, which exhibits good ductility, under varying temperatures (900–1100 ℃) and different strain ratesstrain rates (0.001–10 s ⁻¹). It was found that this single-phase face-centered cubic (FCC) high-entropy alloy shows an abnormal increase in rheological stress in the true stress-true strain curves under strain rates of 0.001 s ⁻¹ and 0.01 s⁻¹ after a strain of 0.5, deviating from conventional patterns. This phenomenon affects the accuracy of both the Zener-Hollomon constitutive model and the hot processing map. Analysis of the microstructure reveals that at low strain rates (0.001 s⁻¹ and 0.01 s⁻¹), the proportion of recrystallized grains is significantly lower than that of subgrains, and within the recrystallized grains, further deformation occurs, leading to sparse dislocations and low-angle grain boundaries. This deformation is caused by the external forces, resulting in the movement of recrystallization boundaries and dislocation slip, thereby disrupting the orientation between points within the grains to no longer be uniformly distributed. At this stage, the recrystallized grains form a small amount of secondary recrystallization in the form of splitting, with the recrystallization mechanism being Continuous Dynamic Recrystallization (CDRX).