Rapid W/SiC reaction induced by laser surface remelting within SiC_f/Ti17 composites

Compared to alloys, metal-matrix composites experience more complicated microstructure evolution and interfacial reactions under extreme thermal conditions during laser additive manufacturing, welding-repairing and laser surface engineering. In this study, a cubic-shaped SiC_f/Ti17 composite is heated by laser surface remelting and the rapid W-SiC reaction within the core-section of SiC fiber located in the molten pool were investigated. As fiber location close to the center of laser spot, severe reaction between W-core and SiC was observed. By applying SEM, XRD, nanoindentation and TEM, the reaction products are confirmed to be W₂C and W₅Si₃. The W₂C has ellipsoid shape with a P-31m space group ordered structure, while W₅Si₃ solidify between W₂C resulting from its lower melting point. Because of the extreme temperature that melt W₅Si₃, the reaction products exhibit different morphology from those produced by solid-state diffusion such as sintering.