Effect of rare earth element Er on microstructure and properties of Al-Si-Cu solder alloy

In order to improve the properties of the brazing alloy Al-7Si-20Cu, a small amount of rare earth (RE) Er was added into Al-7Si-20Cu brazing alloy aiming at examining the effect of different amounts of Er on the physical properties, spreading property and mechanical properties of the solders. Results show that a small amount of Er has no obvious effect on the melting temperature of Al-Si-Cu solder alloy, but can notably improve spreading property of brazing alloy on LF21 surface, especially when the content of Er is Within 0.05-0.1%. According to the examination on the microstructure of AlSiCu brazing alloy, with the increase of Er content the microstructure becomes finer and the length of acicular eutectic Silicon is shortening.