Influence of wet milling duration on the electromagnetic properties and microwave absorption performances of FeCoNiAl_0.2Si_0.3 high-entropy alloy

FeCoNiAl_0.2Si_0.3 high-entropy alloy (HEA) powders with different wet milling durations (2 h, 4 h, 6 h, 8 h, 10 h, 12 h) were synthesized through a mechanical alloying process that combined dry and wet milling. As the wet milling duration increased, the average particle size of the powder gradually decreased and the particle morphology shifted from flaky to irregular shapes. The samples with irregular particles, although they exhibit a reduced ability to attenuate incident electromagnetic waves compared to samples with flake particles, due to their superior impedance matching, demonstrate excellent overall microwave absorption performance. The sample with wet milling duration of 10 h (S10) demonstrated a minimum reflection loss (RLmin) of −60.22 dB at 7.20 GHz and achieved the effective absorption bandwidth (EAB) of 6.48 GHz (10.08 GHz–16.56 GHz) at 1.59 mm. This research offers valuable insights for synthesizing high-performance HEA microwave absorbing materials through mechanical alloying technology.