MICROSTRUCTURE AND DRY SLIDING WEAR RESISTANCE OF LASER CLADDING Ti-Al-Si COMPOSITE COATING

Abstract

In order to improve the wear resistance of Ti alloys, different mass ratios of Ti-Si-Al powders were designed to fabricate hard phases reinforced intermetallic matrix composite coatings on the Ti-6Al-4V substrate by laser cladding. The corresponding coatings were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and high resolution transmission microscopy (HRTEM). The HV-1000 hardness tester and MM200 wear test machine were employed to test the hardness and the wear resistance of the composite coatings, respectively. The composite coatings mainly consisted of the reinforcements of Ti5Si3, Ti3AlC2 and Ti7Al5Si[Formula: see text] and the matrix of Ti3Al, TiAl, TiAl3 and [Formula: see text]-Ti. The micro-hardness of the Ti-35Al-15Si coating was from 956 HV[Formula: see text] to 1130 HV[Formula: see text], which was approximately 3–4 times of the substrate and the highest in the three samples. The wear rate of the Ti-35Al-15Si coating was 0.023[Formula: see text]cm3[Formula: see text][Formula: see text][Formula: see text]min[Formula: see text], which was about 1/4 of the Ti-6Al-4V substrate. It was the lowest in the three samples.