Vacuum brazing technology and microstructure near the interface of Al/18-8 stainless steel

The microstructure performance for vacuum brazing interface of Al/18-8 stainless steel was studied by means of SEM, micro-hardness test and X-ray diffraction (XRD). The test results indicate that the adhesion brazing interface is excellent, there is no porosity or crack near the interface. The microstructure of the brazing joint is mainly composed of equiaxial and column crystal. The fracture morphology of the brazing joint consists mainly of a coarse and gray fiber-shape fracture, and the fracture is mainly the mixed fracture of toughness and cleavage. The brazing interface consists of δ (Al, Fe, Si) and α-Al (Si), without obvious brittleness phase of the high hardness.