Contact reactive brazing of Al7075 alloy using Cu layer deposited by magnetron sputtering.

Plasma bombardment was applied to remove the surface oxide film of 7075 alloy and the deposited Cu layer with thickness of ∼20 μm was attached closely to the surface of 7075 alloy by magnetron sputtering process. The brazing of 7075 alloy using Cu foil was carried out at 580 °C as the contrast test. The results showed that the brazed joints using deposited Cu layer have better microstructure and higher mechanical properties than that of using Cu foil. As brazing temperature increased to 570 °C, the deposited Cu layer was dissolved into the substrate gradually and formed intermetallic compounds. Further increasing brazing temperature, the intermetallic compounds were reduced and the homogenization of microstructure of brazed joints was enhanced. The shear strength of brazed joints increased firstly and then decreased with the increasing of brazing temperature. The maximum shear strength of 38.7 MPa was obtained when brazing temperature was 600 °C. [ABSTRACT FROM AUTHOR]