In Situ Synthesis of Ceramic Reinforcements for Carbon/CuCrZr Joints Brazed with Composite Fillers

Brazing of two kinds of carbon materials including graphite and carbon fiber-reinforced carbon composites to copper alloys has been realized with CuTiH₂ + BN composite fillers. The microstructure characterization reveals that the ceramic reinforcements containing TiN particles and TiB whiskers have been synthesized by in situ reaction of BN additives with Ti discomposed from TiH₂ in the composite filler. The filler layer of the joints is mainly composed of Cu-based solid solutions Cu (ss)] and Ti-Cu intermetallics along with ceramic reinforcements. Furthermore, a continuous thin reaction layer mainly containing TiC is developed at the interface close to the carbon substrates. The growth of TiC layer is mainly controlled by the diffusion of carbon from the substrates into the liquid filler through the TiC layer formed. The interface evolution of the graphite/CuCrZr joints has been discussed. The electrical resistivity of the joining area is relatively low, which highly meets the requirement for the carbon commutator applications.