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 FeCoNiSi0.2 (Si0.2 MEA) with excellent soft magnetic properties and higher ductility using additive manufacturing technology. The microstructure of Si0.2 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 Si0.1 MEA exhibiting the strongest fiber texture. Among the four FeCoNiSix MEAs, Si0.2 MEA demonstrates the best tensile properties (i.e. δ ∼39 %, σ0.2–287 MPA, σb∼551 MPa). The correlation generalized stacking fault energy calculation model indicates that Si0.2 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 Si0.2 MEA exhibit the best soft magnetic properties (Ms:150emu/g, Hc:1.04Oe). These results provide a new paradigm for developing laser additively manufactured soft magnetic medium entropy alloy.

Keywords

• Medium entropy alloy
• Laser additive manufacturing
• Texture engineering
• Generalized stacking fault energy
• Soft magnetic alloys