Additively manufactured FeCoNiSi0.2 alloy with excellent soft magnetic and mechanical properties through texture engineering

Abstract

High-entropy alloys are widely used as structural materials and hold potential as functional materials. This study aims to develop a soft magnetic medium entropy alloy FeCoNiSi_0.2 (Si_0.2 MEA) with excellent soft magnetic properties and higher ductility using additive manufacturing technology. The microstructure of Si_0.2 MEA is characterized by texture and large grains, with a single FCC phase structure. The texture strength of MEA initially increases and then decreases with the addition of Si, with Si_0.1 MEA exhibiting the strongest fiber texture. Among the four FeCoNiSi_x MEAs, Si_0.2 MEA demonstrates the best tensile properties (i.e. δ ∼39 %, σ_0.2–287 MPA, σ_b∼551 MPa). The correlation generalized stacking fault energy calculation model indicates that Si_0.2 MEA has the lowest generalized stacking fault energy (∼7 mJ/m²), suggesting superior ductility. The synergistic effect of texture and large grains promotes the formation of a magnetization “easy axis”, which makes Si_0.2 MEA exhibit the best soft magnetic properties (M_s:150emu/g, H_c:1.04Oe). These results provide a new paradigm for developing laser additively manufactured soft magnetic medium entropy alloy.