Solid-State Diffusion Welding of Commercial Aluminum Alloy with Pure Copper

The aim of this investigation is to study the effect of time and temperature on the solid-state diffusion welding of commercial aluminum alloy 2xxx series with a pure copper at 425 degrees C, 475 degrees C, 500 degrees C, and 525 degrees C during holding times from 15 min to 240 min. The main characterization techniques were optical microscopy, scanning electron microscopy, energy dispersive spectrometry, nanoindentation, microhardness measurements, and x-ray diffraction. Results showed that increasing the temperature and the holding time had an effect on the apparition of the intermetallics at the Al alloy/Cu interface. Five intermetallic phases namely Al2Cu, AlCu, Al3Cu4, Al2Cu3, and Al4Cu9 were identified at the interface. The mechanical properties of the welded joint Al/Cu alloy varied also with the time and temperature. The nanoindentation measurements showed that the highest values of hardness were recorded in AlCu and Al3Cu4 phases. The welding success of these dissimilar metals can be used for battery cables or to form heat exchanger plates for vehicles.