Our recent study has successfully demonstrated the one-step synthesis of homogeneous nanocrystalline (~ 10 nm) single-fcc magnetic CoCrFeNiGax (x = 0.5; 1) high entropy alloy (HEA) powder particles containing low melting element of Ga through short-term high energy ball milling (HEBM). The results of their thermal stability (up to 1300K ±5K) in correlation with their structure, composition and enhancement of magnetic properties during heat treatment, as well as after consolidation by spark plasma sintering (SPS) were investigated including high resolution transmission electron microscopy (HRTEM) and atom probe tomography (APT).

The combination of HEBM and SPS yields homogeneous bulk HEAs with low-melting Ga and enhanced structural, composition, and thermal stability, as well as improved magnetic properties, Ms =55Am2/kg and Tc =750 K, which is 45% and 47 K higher, respectively, compared to conventional melting approaches.

The study was carried out in collaboration with projects: A04, A03, B02, B05, Z01, Z02.

Effect of high energy ball milling, heat treatment and spark plasma sintering on structure, composition, thermal stability and magnetism in CoCrFeNiGax (x = 0.5; 1) high entropy alloys
N. F. Shkodich, T. Smoliarova, H. Ali, B. Eggert, Z. Rao, M. Spasova, I. Tarasov, H. Wende, K. Ollefs, B. Gault, M. Farle
Acta Materialia 284 (2025), 120569.
DOI: https://doi.org/10.1016/j.actamat.2024.120569