Improved mechanical performance of FeCoNiAlMn films through controlled annealing

As soft magnetic materials continue to attract significant attention, investigating their mechanical properties has become increasingly important. In this study, FeCoNiAlMn alloys with varying elemental concentrations and annealing temperatures were examined to evaluate their mechanical behaviour. Alloys were fabricated using DC magnetron sputtering using three separate targets: FeCoNi, Al, and Mn under an argon atmosphere. All films had an approximate thickness of 600 nm. The alloys were investigated in the as-deposited state and after annealing at 400 °C, 600 °C, and 800 °C for 1 h. X-ray Photoelectron Spectroscopy (XPS) was employed to determine the elemental composition of each alloy, while X-ray Diffraction (XRD) analysis revealed variations in crystal structure associated with changes in elemental ratios and heat treatment conditions. The mechanical properties were evaluated using a nanoindenter. The FeCoNi0.8 alloy exhibited a significant improvement in hardness with increasing annealing temperature, reaching approximately 16 GPa when annealed 600 °C, about three times higher than its as-deposited value. In contrast, the Fe1.1CoNiAl1.5Mn5.4 alloy showed a considerable reduction in hardness, decreasing from around 5 GPa for the as-deposited film to approximately 0.9 GPa after annealing at 600 °C.