Effects of micro-arc oxidation pretreatment on residual tensile shear of aluminum alloy-carbon fiber reinforced polymer (CFRP) laser lap joints during aging

Since the mechanical properties of the aluminum alloy/carbon fiber reinforced polymer (CFRP) composite degrade at high temperatures and upon prolonged light exposure, micro-arc oxidation (MAO) is performed on the aluminum alloy/CFRP joints. In order to evaluate the lifetime and failure mechanism of the aluminum alloy/CFRP laser-welded joint for practical engineering applications, aging simulation experiments are conducted systematically. The results show that the directly connected Al/CFRP joint exhibits the worst aging resistance, as manifested by a 48.01% deterioration in the mechanical properties after aging, in addition to peeling failure expanding inward along the interfacial bond gradient direction. In contrast, the Al-MAO/CFRP shows the best aging stability, with the mechanical properties remaining above 90%. This is partly because the thermal barrier effect of the interfacial ceramic layer reduces the inhomogeneity of the interfacial temperature during welding and improves the gradient distribution of the interfacial bonding force. Another factor is that the mechanically locked morphology of the micro-arc oxidized interface inhibits the aging shedding of the interface on the micro-scale, and consequently improves the aging stability of the Al-MAO/CFRP interface substantially. © 2026 Informa UK Limited, trading as Taylor & Francis Group.