Cu foam has previously been investigated and verified to be an excellent interlayer candidate for relieving high residual stress within C/C composite-Nb brazed joints. However, the optimized geometric structure of Cu foam for brazing has never been properly investigated since it was always employed as a reactant for acquiring homogeneous distribution of the interfacial structures in the brazed joints. In this work, graphene reinforced Cu foam composite (G-Cu_f) interlayers were used for brazing C/C composite and Nb. Through the protection effect of graphene on the Cu foam substrate, the impact of porosity and thickness of a structurally intact Cu foam on the joint structure and properties were investigated by finite elemental analysis as well as through experimental studies. By introducing a G-Cu_f interlayer with an optimized porosity of 90% and thickness of 0.15 mm, the shear strength of the C/C composite-Nb brazed joint reached 45 MPa, which is 3.5 times higher than that of the joint brazed directly without an interlayer. The strain energy of the brazed joint assisted by G-Cu_f interlayer reduced from as high as 10.98 × 10^–6 J to 6.90 × 10^–6 J, suggesting that the residual stress was effectively mitigated.

之前已经研究并证实泡沫铜是缓解 C/C 复合材料-Nb 钎焊接头内高残余应力的极好中间层候选材料。然而，用于钎焊的泡沫铜的优化几何结构从未得到适当的研究，因为它一直被用作反应物，以获得钎焊接头中界面结构的均匀分布。在这项工作中，石墨烯增强的泡沫铜复合材料 (G-Cu _f ) 中间层用于钎焊 C/C 复合材料和 Nb。通过石墨烯对泡沫铜基材的保护作用，通过有限元分析和实验研究，研究了结构完整的泡沫铜的孔隙率和厚度对接头结构和性能的影响。通过引入 G-Cu _f在优化孔隙率为 90%、厚度为 0.15 mm 的夹层中，C/C 复合-Nb 钎焊接头的剪切强度达到 45 MPa，是无夹层直接钎焊接头的 3.5 倍。G-Cu _f夹层辅助钎焊接头的应变能从高达 10.98 × 10 ^–6  J 降低到 6.90 × 10 ^–6  J，表明残余应力得到有效缓解。