Tailoring Mechanical and Soft Magnetic Properties in (Fe₇Co6₆Ni6₆)_93-xTa_xAl₇ Multi-Principal Element Alloys: The Role of Ta Addition

The growing demand for high-strength and low-core-loss soft magnetic materials in high-efficiency energy conversion devices necessitates the development of novel alloys that combine excellent mechanical and soft magnetic properties. This work investigated the effect of Ta content on the microstructure and properties of as-cast (Fe₇Co₆Ni₆)93-xTaxAl7 (x=3, 5, 7) multiprincipal element alloys (MPEAs). The alloys featured an FCC matrix, in which Ta addition led to the precipitation of a Ta-rich Laves phase and significant grain refinement. The Ta5 alloy demonstrated an optimal balance of properties, with a yield strength approaching 1 GPa, an elongation of ~10%, a saturation magnetization of 92.88 emu/g, and a coercivity of 446.43 A/m, indicating good strength, ductility, and soft magnetic performance. An appropriate amount of Ta enhanced strength via precipitation and grain-boundary strengthening, while the saturation magnetization showed only a moderate reduction. The coercivity was effectively kept low by the fine, dispersed Co2Ta Laves phases, which minimized domain wall pinning.