Pre-Inscribed Laser Surface Pattering for Increased Joining Strength in Laser Fusion Bonding of CFRP and Zinc-Coated Steel

In this study, we present improved fusion-bonding strength results between carbon fiber-reinforced polyetheretherketone (CFR-PEEK) and zinc-coated steel through the introduction of pre-inscribed laser surface patterns. Optimized laser welding parameters, including laser power, focal position, pitch, number of passes, and clamping pressure, are presented along with parameters for producing the rectangular laser patterns. It was found that for the optimized parameters, the tensile shear strength of the welded samples is improved by as much as 100% when pre-inscribed laser patterns are present. Detailed SEM images of the fractured fusion welded joint samples after the tensile shear test are presented for analysis. The tight bonding between the polymer matrix and the zinc-coated steel inside the formed grooves is found to be the main reason behind the increased tensile shear strength. A comparison of the tensile shear loads for various joining methods is also presented and discussed.