Dual optimization of energy-absorbing intermediate layer for diversified enhancement of heterogeneous brazed joints

The large specific surface area of Cu foam was used to manufacture the high-quality of graphene without crystal defects, and the graphene-reinforced Cu foam (G-Cu) was introduced as an interlayer to join C/C composites and titanium alloy. The foam net structure enabled the molten filler to flow into its pores, reduced the aggregation of Ag-based solid solution, promoted the uniform, and dispersed distribution of various phases. Results showed that the joint shear strength with G-Cu foam interlayer reached 50 MPa, which was twice about directly brazed joint. Due to the isolation and protection of the graphene film, the three-dimensional skeleton structure of foam kept intact, and the ability to relieve residual stress was more fully utilized, thereby further improving the brazed joint strength.