Properties of melt-spun Al-Si-Cu brazing foils

Three kinds of Al-Si-Cu alloys were melt spun into ribbons of about 70~100 μm thickness. According to the results of differential thermal analysis, the melting point of these brazing foils is 3~5℃ lower than as-casting brazing rods. Compared with as-casting brazing rods of compositions similar to the ribbons studied here, the wetting factor and tensile stress of joints are about 20% and 30% higher than as-cast brazing rod, respectivly. Analyzed the microstructure characteristics of brazing alloy and brazed joints, it has been found that the size of grain of ribbons is smaller than 0.6 μm. The chemical and microstructural homogeneity of brazing ribbons result in narrow point ranges, higher strength and corrosion resistance of brazing joints, as well as improving wettability.