Microstructure and corrosion resistance of AlCrFeCoNiCu high-entropy coating by laser deposition on an aluminum alloy

To improve the mechanical and corrosion resistance of an aluminum alloys, laser deposition(LDP) was used to form an ALCrFeCoNiCu high-entropy alloy (HEA) coating on an aluminum alloy surface. The phase structure, microstructure, micro-hardness and corrosion resistance of the HEA coating were investigated using X-ray diffraction (XRD), scanning electronic microscopy with energy-dispersive spectroscopy (SEMEDS), a microhardness tester and an electrochemical workstation. The experiment revealed that the coating had excellent adhesion to the substrate. The HEA coating consisted of body-centered cubic (BCC) and face centered cubic (FCC) phases, while the microstructure was shown to be a typical dendritic structure. The coating had an average micro hardness of 528Hv(0.2) which is five times greater than that of the substrate. Corrosion of the samples was shown to be pitting and intercrystalline corrosion in a 3. 5% NaCl solution, and the corrosion resistance was superior to that of the substrate. Thus, AlCrFeCoNiCu HEA coating has been demonstrated to be an effective way of improving the surface properties of aluminum alloys.