Effect of annealing on the microstructure and properties of a FeMnCoCrNi non-equiatomic high-entropy alloy
Abstract
The development of non-equiatomic high-entropy alloys offers expanded compositional flexibility compared to conventional and equiatomic systems, though their high-temperature behavior remains underexplored. This study investigates a novel Fe32Mn26Co21Cr11Ni10 alloy in both as-cast and annealed states (annealed at 1130 °C). The alloy exhibits a configurational entropy of 12.60 J/(mol·K), stabilizing a single FCC phase with minimal lattice parameter changes (3.619–3.622 Å) between the two states. Annealing transforms the dendritic microstructure into equiaxed grains with annealing twins, enhancing homogeneity. Thermal analysis confirms remarkable stability up to the solidus temperature of 1283 °C. Interestingly, magnetic properties shift from paramagnetic in the as-cast state to ferromagnetic after annealing, with a high Curie temperature of 842 °C. Nanoindentation reveals hardness increasing from 214–229 HV to 258–270 HV and elastic modulus increasing from 185–192 GPa to 197–225 GPa. Deformed surface analysis via AFM demonstrates the formation of much more pronounced and uniform slip bands in the annealed sample, indicative of improved ductility, enhanced dislocation mobility, and reduced grain boundary density. These results underscore the alloy’s potential for high-temperature magneto-structural applications by combining thermal stability, tunable mechanical properties, and emergent ferromagnetism through microstructural engineering. The findings highlight the critical role of annealing in optimizing performance.
Mariusz Hasiak
Head
Amadeusz Łaszcz
Researcher
Michał Biały
PhD Student
