Microstructure and properties of laser clad high-entropy alloy coating on aluminium

ABSTRACTAn AlCrFeNiCuCo high-entropy alloy (HEA) coating was synthesised on an aluminium substrate by laser cladding. Samples were characterised using an optical microscope, X-ray diffraction, scanning electron microscopy with energy-dispersive spectroscopy, a microhardness tester, and an electrochemical workstation. The results showed that the interface between the cladding layer and matrix was sound, while the HEA coating consisted of BCC and FCC solid solutions and an Al-rich phase resulting from substrate dilution. The microstructure of the clad layer comprised both columnar and equiaxed grains. The average microhardness of the coating was 550 HV0.2, and it exhibited better corrosion resistance than the aluminium matrix in a 1 mol L−1 H2SO4 solution. The typical corrosion characteristic of the coating was pitting and localised corrosion.