Microstructure and tribological behaviors of laser cladded CuAlMnTi–xTiC composite coatings at elevated temperature

Abstract

CuAlMnTi-xTiC composite coatings were prepared on Ti6Al4V alloy by laser cladding to enhance its tribological properties. The effects of TiC mass fraction on the friction–wear properties of CuAlMnTi–xTiC composite coatings at high–temperature were investigated using an ball–on–disc tester. The results show that the grains of CuAlMnTi–xTiC composite coatings are refined by the addition of TiC, and the metallurgical bonding is formed between the coating and the substrate. The hardness of CuAlMnTi–15%TiC composite coating is higher 1.98 times than that of CuAlMnTi coating, in which the TiC as wear–resistant framework prevents micro–cutting to enhance wear resistance. The average coefficients of friction of CuAlMnTi–0%TiC, –5%TiC, –10%TiC and –15% TiC composite coatings in the stable wear period are 0.465, 0.491, 0.514, and 0.587, respectively, and the corresponding wear rates are 116.8, 111.3, 107.8, and 95.4 μm3•N–1•mm–1, respectively, showing that the wear rate is decreased with the increase of TiC mass fraction. The wear mechanism is transferred from adhesive wear to abrasive wear and slight oxidation wear by the addition of TiC, which is attributed to the improvement of hardness by the refined grain strengthening effect of TiC.