Effect of Ti and WC on the Microstructure and Mechanical Properties of Laser Cladding AlCoCrFeNi High-Entropy Alloys

To improve the hardness of AlCoCrFeNi high-entropy alloy coatings, Ti and WC are added to the high-entropy alloys in this paper. Composite coatings of AlCoCrFeNi, Ti, and x-WC (x = 3, 6, 9 wt %) on the surface of H13 hot work die steel are prepared by laser cladding. Coatings are characterized by hardness test, electrochemical test, friction and wear experiment, X-ray diffractometer (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), and EBSD (electron backscatter diffraction). The results reveal that the crystal structure of the coatings does not alter after the addition of Ti and WC. Coatings consisting of BCC/B2 and precipitated phases. BCC/B2 phases are mainly Al–Ni, and Fe–Cr phases. The precipitated phases are the WC and TiC phases. The results indicate that the hardness is improved after the addition of Ti and WC. Besides, the wear mechanism becomes different, and the grain size is refined. Coating hardness is increased from 528.9HV0.5 to 625.3HV0.5. Wear mechanisms change to oxidative, adhesive, and abrasive wear with the addition of Ti and WC. The precipitation of the second phase deteriorates the corrosion resistance of the coatings.