Enhanced DC and AC Soft Magnetic Properties of Fe-Co-Ni-Al-Si High-Entropy Alloys via Texture and Iron Segregation

Abstract

The microstructure and soft magnetic properties under direct current (DC) mode and alternating current (AC) mode of FeCoNiAl1−xSix (x = 0.2, 0.4, 0.6) high-entropy alloys (HEAs) are investigated. All the studied HEAs show body-centered cubic (BCC) structures, and the [100] texture is formed in the x = 0.4 HEA. The iron (Fe) segregation at the grain boundaries is helpful in increasing the soft magnetic properties under DC. The FeCoNiAl0.6Si0.4 (x = 0.4) HEA exhibits optimal DC and AC soft magnetic properties, primarily due to the formation of the texture along the easy magnetization axis. The x = 0.4 HEA shows the highest permeability (μi = 344 and μm = 1334) and the smallest coercivity (Hc = 51 A/m), remanence (Br = 132 mT), and hysteresis loss (Pu = 205 J/m3). In comparison to the x = 0.2 HEA and x = 0.6 HEA, the total loss (AC Ps) at 50 Hz of the x = 0.4 HEA is decreased by 15% and 18%, and it is reduced at 950 Hz by 13% and 7%. Our findings can provide a useful approach for developing novel HEAs with increased soft magnetic properties by tuning ferromagnetic elemental segregation and forming the texture along the easy magnetization axis.