Study on laser welding technology of carbon fiber reinforced thermoplastic composite and metal thick plate

According to the requirements of laser connection between thick metal plate and carbon fiber reinforced thermoplastic composite (CFRTP), the existing connection process is improved, and the laser focusing position is adjusted from the upper surface of the thick metal plate to the side, so as to ensure that the resin of the connection interface is fully melted without increasing the laser power. At the same time, the influence of heat source distance on the interface morphology and mechanical properties of the joint was studied by combining experimental research and finite element simulation. The results show that the interface can be divided into softening zone, melting zone and decomposition zone, and the simulation results are in good agreement with the test results, in which the melting zone width ratio increases first and then decreases with the increase of the connection distance. At the same time, the joint shear force also has a similar change law, and the joint shear force is the largest (1.7 kN) when the heat source distance is 6 mm, indicating that the mechanical properties of the joint mainly depend on the width ratio of the melting zone, the reason is that the resin in the melting zone is embedded in the metal surface microstructure and forms a firm interlocking interface after solidification. When the heat source distance is small, the interface temperature is too high, resulting in an increase in the decomposition zone width ratio and a decrease in the melting zone width ratio. However, the heat input of the interface is insufficient and the width of the melting zone is insufficient.