In this study, the weldability of single-sided ultrasonic welding of 4-mm-thick carbon fiber/Nylon 66 composite was studied. Extensive welding was performed, and the weld microstructures, fractographies, and appearances of welded joints were examined and analyzed. It was found that the strengths of single-sided ultrasonic welded (SSUWed) joints made with proper welding variables are comparable to that of the ultrasonic welded joints. The solid SSUWed joints with introducing a gap of 1.0 mm can be produced with the use of double-pulse ultrasonic vibration schedule. The robust welding variables include a weld pressure of 0.17 MPa and a weld time of 1.3 s for the first vibration pulse, 5-s cooling, and a weld time of 1.3 s for the second vibration pulse. Microstructure analyses and mechanical testing of the welds revealed that the application of second ultrasonic pulse caused the melting of the materials at periphery of the existing weld, and consequently resulted in an increase in weld area. The use of the second vibration pulse not only improved the strength but also decreased the scatter in strength of the ultrasonic welded 4-mm-thick carbon fiber/Nylon 66 composite. The double-pulse vibration schedule improves the robustness of the SSUW and increases the flexibility of product designs that rely on the ultrasonic welding for assembly.

在这项研究中，研究了 4 毫米厚的碳纤维/尼龙 66 复合材料单面超声波焊接的可焊性。进行了广泛的焊接，并对焊接接头的显微组织、断口和外观进行了检查和分析。发现使用适当焊接变量制成的单面超声波焊接 (SSUWed) 接头的强度与超声波焊接接头的强度相当。可以使用双脉冲超声波振动程序生产具有 1.0 mm 间隙的实心 SSUWed 接头。稳健的焊接变量包括 0.17 MPa 的焊接压力和第一个振动脉冲的焊接时间为 1.3 秒，冷却时间为 5 秒，第二个振动脉冲的焊接时间为 1.3 秒。焊缝的显微组织分析和力学测试表明，第二次超声脉冲的应用导致现有焊缝周边材料熔化，从而导致焊缝面积增加。使用第二次振动脉冲不仅提高了强度，而且还降低了超声波焊接的 4 毫米厚碳纤维/尼龙 66 复合材料的强度分散。双脉冲振动计划提高了 SSUW 的稳健性，并增加了依赖超声波焊接进行组装的产品设计的灵活性。使用第二次振动脉冲不仅提高了强度，而且还降低了超声波焊接的 4 毫米厚碳纤维/尼龙 66 复合材料的强度分散。双脉冲振动计划提高了 SSUW 的稳健性，并增加了依赖超声波焊接进行组装的产品设计的灵活性。使用第二次振动脉冲不仅提高了强度，而且还降低了超声波焊接的 4 毫米厚碳纤维/尼龙 66 复合材料的强度分散。双脉冲振动计划提高了 SSUW 的稳健性，并增加了依赖超声波焊接进行组装的产品设计的灵活性。