碳纤维增强热塑性复合材料与金属厚板激光连接工艺研究

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

  • 摘要: 针对金属厚板与碳纤维增强热塑性复合材料(CFRTP)激光连接需求,改进了现有连接工艺,将激光聚焦位置由金属厚板上表面调整为侧面,在不提高激光功率的同时保证连接界面树脂充分熔化。同时,采用试验研究和有限元模拟相结合的方法,研究了热源距离对连接界面形貌和接头力学性能的影响规律。结果表明,连接界面可分为软化区、熔化区、分解区三个区域,且温度场仿真结果与试验结果一致性良好,其中熔化区宽度占比随着连接距离的增加先增大后减少;同时,接头剪切力也具有类似的变化规律,且热源距离为6 mm时接头剪切力最大(1.7 kN),表明接头力学性能主要取决于熔化区宽度占比,其原因为熔化区的树脂嵌入金属表面微结构中,凝固后形成牢固的互锁界面。热源距离较小时连接界面温度过高,导致分解区宽度占比增加、熔化区宽度占比降低;而较远时连接界面热输入不足,熔化区宽度占比不足。

     

    Abstract: 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.

     

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