Brazing of C/C composite and Ti-6Al-4V with graphene strengthened AgCuTi filler: Effects of graphene on wettability, microstructure and mechanical properties

Graphene nanosheets (GNSs) strengthened AgCuTi composite filler (AgCuTiG) was used to braze C/C composite and Ti-6Al-4V. The effects of GNSs on the wettability of AgCuTiG filler on the C/C composite surface and the interfacial microstructure and mechanical properties of brazed joints were investigated. The results indicate that the addition of GNSs reduced the wettability of AgCuTiG. The interfacial microstructure of brazed joints evolved with the addition of GNSs, where Ti3Cu4 and TiCu4 were converted to TiCu and the thickness of the reaction layer adjacent to the base material decreased. The maximum shear strength of joints brazed at 0.3wt% GNSs was 23.3 MPa (880 °C/10 min). Further adding GNSs deteriorated the shear strength of the joints. Fracture of the joints occurred in the C/C composite substrate and the TiC layer adjacent to C/C composite. Keywords: Brazing, Graphene nanosheets, Mechanical properties, Microstructure, Wetting