Carbon fiber reinforced Composites-TC4 titanium alloy laser stir welding with interfacial micro-texturing pretreatment

To investigate the influence of interfacial micro-textures on the performance of dissimilar joints between carbon fiber reinforced thermosetting composites (CFRTS) and TC4 titanium alloy, a finite element model (FEM) of CFRTS-TC4 laser welding is developed and validated. Temperature distribution within the joint is numerically simulated and experimentally characterized. Although a slight deviation is observed between the experimental and simulated temperature values, both datasets demonstrate consistent trends. Temperature profiles are systematically analyzed at three critical locations: the top surface of the TC4 substrate, the bonding interface, and the CFRTS surface. Comparative analysis is subsequently performed to evaluate the thermal behavior of joints with and without laser micro-texturing pretreatment. Results reveal that micro-textured joints exhibite lower peak temperatures while maintaining similar overall temperature evolution patterns compared to non-textured counterparts. This thermal reduction is attributed to the geometric transformation of the contact interface from a planar configuration to a three-dimensional grid structure induced by laser micro-texturing. The textured grid geometry enhances the surface area exposed to air, thereby improving convective heat dissipation. Additionally, the micro-texture facilitates superior infiltration of PA6 matrix resin into the interstices between carbon fibers and the titanium substrate. Consequently, this approach effectively minimizes thermal defects and significantly enhanced the mechanical strength of the dissimilar joint.