An additional hole to compensate for mechanical property of thermoset composite and aluminum alloy joint during resistance welding

A hole in the center of the aluminum (Al) alloy was processed to compensate for the mechanical properties of resistance welded joints of the carbon fiber reinforced epoxy resin matrix (CF/Epoxy) laminate and Al alloy for solving the problem of poor bonding quality in the center of the joint due to uneven temperature distribution in the resistance welding process. The resistance welded lap configuration of the upper Al and the lower laminate was employed, and through holes with a different diameter (dh) were prefabricated on the upper Al alloy plates. The molten polyetherimide (PEI) resin was bonded to the surfaces of the samples on both sides under the action of Joule heat, and the excess PEI resin filled the prefabricated through-hole of the Al alloy plate under pressure and realized the jointing of the 6063Al alloy plate and the CF/Epoxy laminate. The micro-morphology of the welded interface was characterized by scanning electron microscopy (SEM), and the heat distribution of the sample was simulated using COMSOL. The tensile shear force of the joint was tested, which rises with an increase of dh. The failure interface was analyzed in detail, which showed a strong correlation with dh.