在钎缝左侧有裸露的基体，说明此处钎料强度高于界面结合强度；在钎缝右侧出现裸露的脆性金属间化合物，通过能谱分析主要为CuAl₂相及α-Al相。说明裂纹起裂源主要产生于脆硬金属间化合物界面，由于CuAl₂金属间化合物层较薄，故裂纹随后沿着α-Al扩展。

There is an exposed matrix on the left side of the brazing seam, indicating that the strength of the brazing filler metal is higher than the interface bonding strength; there are exposed brittle intermetallic compounds on the right side of the brazing seam, which are mainly CuAl2 phase and α-Al phase through energy spectrum analysis. It shows that the crack initiation source mainly occurs at the interface of brittle and hard intermetallic compounds. Because the CuAl2 intermetallic compound layer is thin, the cracks subsequently propagate along α-Al.