Borides of preferred orientation formed in the transient liquid phase joint of γ′-strengthened Co-base single crystal superalloy

γ′-Strengthened Co-base single crystal superalloy was jointed with B-Ni76CrWB alloy powder by transient liquid phase bonding. The growth mechanism of the borides of preferred orientation formed in the diffusion affect zone of the joint was investigated. Results indicated that the prepared borides were (Co,W,Ta)3B2 and were long plate-shaped in three dimensions. The preferred growth orientation of the borides in the diffusion affect zone of transient liquid phase joint was 〈0 0 1〉 matrix, enjoying a significant orientation relationship with the substrate.