Microstructure of SiC/Al composite coating by CO2 laser cladding

SiC/Al composite materials have some of the excellent performance in high strength, pre-high temperature and anti-erosion and anti-wear, it is available in many important fields, for example, aircraft, aerospace, automobile and national defence. A lot of researches are focused in bulk composite material produced by casting or mold-press technologies. SiC reinforced metal surface composite coating by laser cladding is interested in hardfacing technology, up to now, however, reinforced materials are almost steels, a few papers of SiC/Al reinforced by laser cladding are there. In the paper, SiC/Al composite coating by laser particle injection/cladding has been researched. Green SiCp powder of granularity 20∼40µm and purity 99.99% as well as base materials LY12 with contents of 3.8∼4.0%Cu, 1.2∼1.8Mg, 0.3∼0.99%Mn and balance Al are used. It is shown that SiC/Al reinforced composite coatings has been successfully made by laser injection. In composite coatings, the main phases are SiC particles and Al, SiC particles is uniformly distributed in Al solution. There are three crystallines of 3C, 6C and 5H for SiC particles in coating, in which the crystallines of 3C and 6H belong to the original one, the crystalline of 5H is produced during laser cladding. In addition to SiC and Al, a very few of Al4SiC4 and Si are observed in the coatings.