Intermetallic compounds at aluminum-to-copper electrical interfaces: effect of temperature and electric current

The effects of intermetallic compounds on the electrical and mechanical properties of bimetallic friction welded Al-Cu joints was studied. The formation and growth of intermetallic compounds was studied in the temperature ranges 200-525/spl deg/C. In addition, the effect of electrical current on the morphology and kinetics of formation of intermetallic compounds of bimetallic friction welded aluminum-copper joints was studied in the temperature ranges 200-500/spl deg/C that was realized by heating Al-Cu joints with an ac current of different intensities (400-1000 A). The contact resistance was found to increase linearly with the thickness of the intermetallics. The presence of an electrical field greatly accelerates the kinetics of formation of intermetallic phases and alters significantly their morphology. The growth kinetics of intermetallic phases under the influence of electrical current is much higher than that under diffusion annealing in furnace.