Effect of Homogenization on Microstructure and Hardness of Arc-Melted FeCoNiMn High Entropy Alloy During High-Pressure Torsion (HPT)

The effect of homogenization on microstructure and hardness of FeCoNiMn high entropy alloy was investigated during the high-pressure torsion. Transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD), and Vickers microhardness were used to evaluate the microstructure and mechanical properties. The as-cast alloy showed a subgrain structure in the central region, while the homogenized alloy revealed the nano-sized grains. In the half-radius, both samples revealed an ultra-fine grained structure. After 10 revolutions, the grain size in the half-radius of the as-cast and homogenized discs reached ~58 and ~44 nm, respectively. The hardness of the homogenized sample was ~440 and ~435 Hv, and that of the as-cast one was ~390 and ~400 Hv in the center and half-radius. The homogenization could affect the microstructure and hardness of the FeCoNiMn HEA during HPT.