Laser cladding of Ti-base composite coatings on Ti6Al4V substrate

Abstract

With preplaced Ti6Al4V + Cr3C2 powder mixtures, the Ti-base composite coatings with in-suit synthesis TiC were obtained by laser cladding on Ti6Al4V substrate. The effects of the ceramic phase (TiC) and the matrix on microhardness of the coatings were also studied by addition of TiC, Cr and Mo into the coatings respectively. The results showed that, there were three typical TiC, i.e. the peritectic (dendrite) TiC, eutectic (boundary) TiC and supersaturated-precipitation (inner) TiC in the coating obtained. With the increase of Cr3C2 added to powder mixtures, the microhardness of the coatings increased dramatically. However, the cracks also appeared when the percentage of Cr3C2 was 20 wt.%. The increase of TiC in the coating could improve the michardness observably. The addition of Cr and Mo with large amount could smooth the microhardness curves and decrease the fluctuation of microhardness, but could not effectively improve the hardness of the coatings.With preplaced Ti6Al4V + Cr3C2 powder mixtures, the Ti-base composite coatings with in-suit synthesis TiC were obtained by laser cladding on Ti6Al4V substrate. The effects of the ceramic phase (TiC) and the matrix on microhardness of the coatings were also studied by addition of TiC, Cr and Mo into the coatings respectively. The results showed that, there were three typical TiC, i.e. the peritectic (dendrite) TiC, eutectic (boundary) TiC and supersaturated-precipitation (inner) TiC in the coating obtained. With the increase of Cr3C2 added to powder mixtures, the microhardness of the coatings increased dramatically. However, the cracks also appeared when the percentage of Cr3C2 was 20 wt.%. The increase of TiC in the coating could improve the michardness observably. The addition of Cr and Mo with large amount could smooth the microhardness curves and decrease the fluctuation of microhardness, but could not effectively improve the hardness of the coatings.