Microstructural evolution and dynamic recrystallization in Fe50Mn30Co10Cr10 medium entropy alloy under hot compression

Abstract

This comprehensive study investigates the recrystallization behavior and deformation mechanisms of the Fe50Mn30Co10Cr10 alloy during hot compression conditions. The alloy undergoes discontinuous dynamic recrystallization, evidenced by necklace-like structures at grain boundaries, competing with the initial hexagonal close-packed (HCP) phase and γ→ε reversion. Early deformation is dominated by strain-induced martensite transformation, twinning, with slip with strain partitioning at the end of deformation. The developed Zener-Hollomon equation, validated experimentally, shows a constant activation energy of 126.96 kJ/mol. Stress-strain curves indicate that recrystallization only partially compensates for hardening effects, with no significant peaks observed. The work hardening curve exhibits significant oscillations due to encounters with pre-existing thermal HCP layers, influencing the work hardening rate. Energy efficiency maps based on temperature and strain rate identify optimal deformation conditions at temperatures ranges of 710–750 °C and strain rates of 0.0025–0.0035 s⁻1. This study provides a deeper understanding of the alloy's behavior, offering insights into the interplay between recrystallization, HCP phase formation, and twin generation. These findings contribute to the optimization of the alloy's mechanical properties for industrial applications.

Keywords

• Fe50Mn30Co10Cr10 medium entropy alloy
• Recrystallization dynamics
• Hot compression
• Microstructural evolution