In this study, the Ti-Al-Si + xTiC (x = 0, 2, 6, 10 wt.%) composite coatings, each with a different content of TiC were fabricated on a Ti-6Al-4V alloy by laser surface cladding. The microstructure of the prepared coatings was analyzed by the scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The microhardness and the wear resistance of these coatings were also evaluated. The results show that α-Ti, Ti3Al, Ti5Si3, TiAl3, TiAl, Ti3AlC2 and TiC particles can be found in the composites. The microstructure can obviously be refined by increasing the content of TiC particles, while the microhardness increases and the coefficient of friction decreases. The Ti-Al-Si-6TiC composite shows the best wear resistance, owing to its relatively fine microstructure and high content of TiC particles. The microhardness of this coating is 5.3 times that of the substrate, while the wear rate is only 0.43 times. However, when the content of TiC was up to 10 wt.%, the original TiC could not be dissolved completely during the laser cladding process, leading to formation of cracks on the coatings.

In this study, CoCrNiMox (x = 0, 1, 3 and 5, wt.%) alloy coatings were fabricated on the surface of low carbon steel by laser surface cladding. The scanning electron microscope (SEM), energy dispersive spectrometer (EDS), and X-ray diffraction (XRD) were used to analyze the microstructure and phases of the prepared coatings. The microhardness and wear resistance of these coating were also evaluated. The results showeded that a single-phase face-centered cubic (FCC) structure generated by the CoCrNi ternary compound in all the coatings, the σ phase, and the Mu (μ) phase, enriched with Cr and Mo and originated with additional Mo, exhibited a lamellar structure. The content of FCC single-phase structure in the coating gradually decreases with the increasing of Mo because the addition of Mo can promote the precipitation of the σ phase and the μ phase. Among all the laser cladded coatings, the CoCrNiMo5 alloy coating shows the best properties, owing to the higher proportion of intermetallic compounds in the σ phase and the μ phase, which can provide enhanced performance. This exhibited the narrowest wear scar width and showed the fatigue wear mechanism.