Ga-induced formation of L6₀ nanoprecipitates in Fe-Co-V magnetic alloys: A strategy for strength enhancement

High-strength Fe₄₉Co₄₉V₂ alloys exhibit substantial application potential in high-performance electromagnetic devices. Current research predominantly achieves strengthening by introducing the precipitation of submicron and microscale second phases, or by incorporating pre-synthesized particles. In this work, we report the successful induction of L6₀ coherent nanoprecipitates in Fe₄₉Co₄₉V₂ alloys through Ga addition. These L6₀ nanoprecipitates possess a tetragonal crystal structure, with a narrow size distribution ranging from 2 to 5 nm. The coercivity of the Ga-doped alloy increases marginally by merely 90 A/m, which is attributed to the slight reduction in saturation magnetization induced by the addition of Ga. In contrast, the compressive yield strength is remarkably enhanced by 150 MPa, corresponding to a relative increment of nearly 43%. This significant strengthening effect stems from a synergistic mechanism involving indirect strengthening via the increase in dislocation density and direct strengthening through the dislocation-cutting effect of the L6₀ nanoprecipitates. And after a 773 K for 100 h of aging treatment, the nanoprecipitates do not become coarse, exhibiting excellent thermal stability. This study demonstrates the excellent strengthening efficiency of Ga-induced L6₀ nanoprecipitates, thereby providing a novel strategy for the development of high-performance Fe-Co-V-based magnetic materials.