MICROSTRUCTURE AND WEAR-RESISTANT PROPERTIES OF WC/SS316L COMPOSITE COATINGS PREPARED BY SUPERSONIC LASER DEPOSITION

摘要

Supersonic laser deposition (SLD) is a newly developed coating method which combines the supersonic powder jet found in cold spray (CS) with synchronous laser heating of the deposition zone. The addition of laser heat energy into CS enables a change in the thermodynamic state of impacting particles and substrate, thereby significantly lowering the critical deposition velocities required for effective coating formation and allowing the range of materials deposited to expand to higher strength materials which are of considerable engineering interest. This paper presents the ability of SLD technique to deposit hard metal matrix composite (MMC) coatings, such as WC/SS316L. The focus of this research is on the comparison between composite coatings produced with conventional CS and those produced with SLD. The microstructure evolution, mechanical deformation mechanisms, correlation between functional properties and process parameters were elaborated in detail. The experimental results show that with the assistance of laser irradiation, WC/SS316L composite coatings can be successfully deposited using SLD. The obtained coatings are superior to that processed with CS, because SLD can improve the deposition efficiency, coating density, interface bonding as compared to CS due to the softening of particle and substrate by laser irradiation. It can be found that SLD is capable of depositing high strength MMC coatings with good quality, thus exhibiting great potential in the field of metal 3D printing.