铝基复合材料；真空钎焊；接头强度；断裂分析

Fracture Mode and Joint Strength for Brazing of SiCp/LY12 Metal Matrix Composite with Al-Cu-Si-Mg Filler

摘要:

采用Al-28Cu-5Si-2Mg钎料，在真空高频感应条件下对SiCp/LY12复合材料进行了钎焊连接。试验结果表明：钎焊温度、保温时间、SiC颗粒的体积分数以及焊后时效处理均会影响SiCp/2024Al复合材料钎焊接头的连接强度：钎缝中有少量SiC颗粒存在，且分布不均匀。在靠近母材处出现贫化区，在钎缝中心两侧有较小的集聚区。SiCp/LY12复合材料钎焊接头的断裂是由于钎缝金属中的SiC颗粒成为裂源，裂纹沿钎缝作低能量撕裂所致。

Abstract:

The brazing of SiC particulate reinforced LY12 alloy matrix composite has been carried out by using the high-frequency induction vacuum brazing process with Al-28Cu-5Si-2Mg filler.The results showed that brazing temperature, holding time, SiC particle volume percentage and post heat treatment condition combine to influence the joint strength of SiCp/LY12. The SiC particles occur in the brazing seam and the distribution of SiC particles in the joint is not as uniform as that in the composites. Particle-poor zones in the joint exist near the base metal, and particle-rich zones exist in the center of the brazing seam. In addition, the results indicate that the failure of the composite is predominantly initiated by microcracks initiating at the SiC particle in the brazing seam and propagated along it with low energy.