Interstitial boron-doped FeCoNiCr high entropy alloys with excellent electromagnetic-wave absorption and resistance to harsh environments

High entropy alloys (HEAs) are new promising electromagnetic-wave absorbing (EMA) materials due to their advantages in terms of corrosion resistance and high electrical conductivity. In the present work, FeCoNiCrBx (x = 0, 0.01, 0.05, 0.1, and 0.5) HEAs were prepared by a 3D high-energy ball-milling method. There was a phase change from face-centered cubic to body-centered cubic in the FeCoNiCrBx HEAs as the B content increased, which led to anomalous changes in mechanical properties, static magnetic properties and corrosion resistance. By tuning B contents, FeCoNiCrB0.05 HEAs delivered excellent electromagnetic-wave absorption performances. The minimum reflection loss (RLmin) values reached −62.5 dB at 11.74 GHz as thin as 2.11 mm, and the widest bandwidth was 5.78 GHz (11.90–17.68 GHz). In addition, B-doped FeCoNiCr HEAs had excellent mechanical properties, corrosion resistance and high temperature oxidation resistance. This work has important significance for the exploration of practical EMA materials that are resistant to harsh environments.