Weldability and mechanical properties of dissimilar aluminum-copper lap joints made by friction stir welding

摘要

Lap joints of 1060 aluminum alloy and commercially pure copper was produced by friction stir welding and the effect of welding speed on interface morphology, microstructure, and joint strength was inves-tigated. The experimental results revealed that in the aluminum close to the Al/Cu interface, a dark area was formed. In this area the intermetallic compounds of Al_4Cu_9 and Al_2Cu, and some microcracks were detected. The frequency of such microcracks decreased with increasing welding speed. On the other hand, at higher welding speeds of 118 and 190 mm/min, the cavity defects were formed inside the joints as a result of insufficient heat input. The results of tensile shear test revealed that the maximum tensile shear strength of joint was obtained at welding speed of 95 mm/min. At this welding speed, no cavity defects, and few microcracks were observed in the weld.