Improvement of interfacial thermal contact conductance and mechanical performance of metal-composite joint via controlling anchoring structures

This study discussed the interfacial heat conduction in depth during the laser welding of metal to composite by constructing rough morphologies adopting the laser ablation method. Results revealed the interface temperature was significantly elevated, reaching 375°C under a line spacing of 0.4 mm, which was higher 45°C than without treatment. For one thing, the increased surface roughness reduced the heat loss and caused the heat concentration at the interface. For another thing, the expanded contact area improved the wettability and strengthened the physical adsorption, and the highest work of adhesion was increased to 49mJ/mm², reaching 1.3 times of those without treatment. The thermal contact resistance was thus decreased, which was confirmed by finite element analysis. Finally, the maximum tensile-shear force and strength of joints were 4171 N and 23 MPa, which was 3.7 times and 3.9 times of those joints without treatment. Additionally, the fatigue life and anti-salty corrosion of joints were improved, providing an effective method for further application.