• Laser surface treatment significantly enhances the long-term reliability of friction lap welded aluminum-polymer composite joints, reducing tensile shear force loss from 91% after 7 days to only 26% after 35 days of accelerated aging.
• The improved joint reliability is attributed to micro-mechanical interlocking and favorable stress distribution at the interface, preventing interfacial fracture.
• The study addresses a critical gap in understanding thermal degradation effects on metal-polymer hybrid joints, promoting their engineering applications.
• The combination of friction lap welding and laser surface treatment offers a promising approach for robust dissimilar material joining in lightweight structures.