Rapid solidification joining of Cu/Ni-matrix heterogeneous alloy foils

The rapid solidification joining of quenched Cu-13.5% Sn/Ni-19.8% Sn heterogeneous alloy foils with the thickness of 40~60μm was performed by a micro-type capacitor discharge welding machine and the microstructural morphology of joint was investigated as well as the effect of welding parameters on shearing strength of joint were researched.The results indicate that the capacitor discharge welding can realize the rapid solidification joining of quenched Cu-13.5% Sn/Ni-19.8% Sn dissimilar alloy foils.The joint consists of a nugget and fusion zone and the nugget is characterized by regular oblate spheroid with the major and minor diameters are 100 μm and 60 μm respectively.The nugget is mainly composed of blocky and stripy Ni-rich phase,fine and compact Cu_13.7Sn columnar crystals and a-Cu phase which distributed with the a-Cu phase.The bonding zone width is about 2~3 μm.The welding parameters have obvious influence on the shearing strength of joint and the favorable welding parameters are C=3 300 mf,F=12 N,U=75 V,D=0.18 mm,and the shearing strength of joint up to 590 MPa.