Effect of laser power on microstructure and properties of laser cladding AlCoCrNiSiTi0.5 high-entropy alloy coatings

Using varying laser powers, an AlCoCrNiSiTi 0.5 high-entropy alloy (HEA) coating was applied to the surface of TC4 titanium alloy. The microstructure and phase composition of the coating were examined using several analytical techniques, including energy spectrometer (EDS), scanning electron microscopy (SEM), and X-ray diffraction (XRD), etc., and Vickers hardness tester was used to test the coating’s microhardness at various laser powers. Studies indicate that the coating is mostly made up of the following phases: BCC, FCC, α-Ti, β-Ti, (Si, Al) 2 Cr, (Ni, Co)Ti 2 ; The coating’s mean hardness under different powers (1400 W, 1600 W, 1800 W) is 1047.87 HV, 1012.68 HV, and 846.72 HV, which is about 2∼3 times of the matrix hardness (347.27 HV). Powder overburning will occur at laser energies greater than 1800 W. The elements evaporate, thereby reducing the microhardness of the coating. The hardness of TC4 titanium alloy can be greatly increased by applying an AlCoCrNiSiTi 0.5 HEA coating.