Mechanosynthesis, characterization, and cytotoxic evaluation of soft ferromagnetic non-equiatomic high entropy alloys in the system Al10+xM12-xFe35Mn23Ni20 (M = Cr, Mo; x = 0, 0.2)

This study investigates the synthesis and characterization of non-equiatomic high-entropy alloys (HEAs) within the Al_10+xM_12-xFe₃₅Mn₂₃Ni₂₀ system (where M = Cr, Mo; x = 0, 0.2). Empirical mathematical models were employed to predict the formation of single-phase structures, which were then verified experimentally. The HEAs were synthesized via mechanosynthesis. The influence of ethanol as a process control agent (PCA) was also evaluated. High-energy ball milling for 120 min yielded the desired HEAs. A single-phase structure was observed for the system with Cr, whereas multiphase structures were observed when Cr was substituted for Mo. The synthesized materials were characterized structurally, microstructurally, elementally, thermally, and magnetically. The use of PCA significantly influences various properties, including particle size, phase formation, thermal-magnetic behavior, and cytotoxicity. While PCA generally improves the particle size distribution, it also promotes the formation of multiphase structures in some cases. Notably, PCA treatment led to a significant increase in the saturation magnetization. Unexpectedly, PCA diminished the cytotoxicity of HEAs. All the products exhibited thermal stability up to 1100 K and showed a tendency for nitrogen absorption. The cytotoxic effects of the synthesized HEAs were evaluated for the first time in healthy human kidney cells (HEK 293T cell line) and tumor cells (C6 glioma cell line). Notably, HEAs synthesized without PCA exhibited significant cytotoxicity, significantly reducing the viability of tumor cells (∼70-40 %), while maintaining good biocompatibility with healthy kidney cells. These findings suggest potential biomedical applications for these HEAs.