Brazing of Boron Carbide by Cu-Alloys: Interface Interaction and Mechanical Properties of Joints

Boron carbide is one of the most promising structural ceramics; therefore its joining to other ceramics and metals is of technological importance. In this study, interface interactions and joints strength were studied in various cases of B 4 C/Cu based fillers (Cu-9at%B, Cu-4.5at%Ti and Ticusil®). The fillers partially wet B 4 C (q < 50 0 ), but the interface composition and morphology are different. In the B 4 C/Cu-9at.%B system no new phases are detected at the interface, while the formation of TiB 2 takes place in the case B 4 C/Cu-4.5at%Ti, and a double layer containing TiB 2 and TiC is formed at the B 4 C/Ticusil® interface. The maximal shear stress for B 4 C/B 4 C joints breakage was obtained for the Cu-9at.%B brazing alloy which displays partial wetting without the formation of brittle phases at the ceramic/metal interface. This study shows that improved wetting is essential but not sufficient in order to obtain strong bonding between B 4 C and the fillers examined.