Synergistic enhancement of 6061 Al/CFRTP joints via laser texturing and chemical etching process for fused deposition modeling

Integrated metal/thermoplastic manufacturing is the trend for industrial applications due to lightweight. However, the joining reliability of metal and carbon fiber reinforced thermoplastic (CFRTP) hybrid joints is relatively low owing to the inherent physical incompatibility, which constrains the development of lightweight integrated components. In this work, the micro-cross pits with a certain direction were fabricated by laser texturing process on the 6061 Al surface, and the nanostructure was processed by chemical etching process to enhance the 6061 Al/CFRTP nylon 6 (PA6) hybrid joints. The surface free energy and roughness were significantly increased at the bonding interface. The tensile-shear strength of 6061 Al/CFRTP joint substantially increased, then gradually declined with the increase of chemical etching time. The results showed that the Al-O-C bond was formatted on bonding interface and the diffusion of elements at the interface of dual-scale processed samples was wider, promoting the joining strength at the joining interface. The laser textured sample with the optimized chemical etching time (30 s) exhibited the maximum shear-tensile strength of 11.23 MPa, which increased by 348% relative to untreated cases. The integrated preparation of 6061 Al/CFRTP joints was achieved via the fused deposition modeling process with dual-scale modification modulation, which breaks through the single structure limitation of traditional metal/thermoplastics joints.