Microstructure and Properties of AlCoCrFeNiSi High-Entropy Alloy Coating on AISI 304 Stainless Steel by Laser Cladding

In this paper, to improve the hardness and wear resistance, AlCoCrFeNiSi HEA coatings were synthesized on AISI 304 stainless steel by laser cladding. The microstructure, chemical composition, constituent phases, microhardness, wear resistance and corrosion resistance of the coating were analyzed by scanning electron microscopy (SEM), energy-dispersive spectrometer (EDS), x-ray diffraction (XRD), Vickers microhardness tester, pin-on-disk tribological tester and electrochemical workstation, respectively. The experimental results showed that the coating possessed a single body-centered cubic (BCC) phase structure (Fe-Cr). Si element was dissolved into Fe-Cr solid solution, resulting in severe lattice distortion. The dislocation density of the coating was as high as 1.07 × 1014 m−2. Therefore, the microhardness (630.36 HV0.3) of the HEA coating was significantly improved by the effect of solid solution strengthening and dislocation strengthening. The coating exhibited excellent wear resistance, and abrasive wear was effectively avoided. The wear mechanism of the coating involved mainly oxidation wear and slight adhesion wear. The corrosion resistance of the coating was better than that of AISI 304 stainless steel in 3.5% NaCl solution. In conclusion, the AlCoCrFeNiSi HEA coating prepared by laser cladding can provide excellent wear protection to stainless steel at no expense to its own corrosion resistance.