Enhanced Interfacial Thermal Contact Conductance and Mechanical Performance of Metal‐Composite Joint With a Hybrid Surface Pre‐Treating Method

ABSTRACT This work proposed a hybrid surface pre‐treatment method to enhance the laser joining strength of aluminum (Al) alloy/carbon fiber‐reinforced thermoplastic composite (CFRTP) joint. This hybrid approach involved incorporating polyamide 66 (PA66) with Al particles as an interlayer at the Al alloy/CFRTP interface and introducing microtextures on the Al alloy. The influence of the interlayer thickness on the joining strength of texturing Al alloy/CFRTP was discussed. Results indicated that using this hybrid method increased the joining strength to approximately 153% compared to when no interlayer was used. A maximum joining strength of 22.7 ± 0.4 MPa was achieved with a 69 μm thickness interlayer. The interlayer used to fill deep microstructures improved thermal transfer and strengthened physical interlocking at the interface. With an interlayer thickness of 69 μm, the resin filling rate reached 100%, and the interfacial temperature peaked at 373°C, which was 34°C higher than that without an interlayer. The digital image correlation (DIC) results confirmed the strain of the joint was decreased. Additionally, the improved salt spray corrosion resistance and fatigue performance demonstrated the potential of this approach for broader engineering applications.