Ultrasonic joining of aluminum/titanium joints for hybrid lightweight applications

混合动力轻量化设计在交通工程和航空航天工业中主导着未来车辆概念的发展。为了实现这样的多材料系统，适当和有效的连接技术是必要的。在这个项目中，超声波金属焊接将被研究，以实现铝钛混合接头在固态。采用先进的工艺控制和新型焊接工具，选择重要的结构铝和钛合金生产高强度接头。为了确定结构应用的最佳工艺变量，将研究超声点焊和扭转焊接技术的直接比较。对超声波焊接过程中的运动学进行了详细的实验研究，并采用激光测振仪对实验结果进行了在线检测。采用现代统计方法进行试验设计，确定了焊接力、振动振幅和焊接能量等工艺参数。粘合现象与工艺变量及其特定工艺参数有关，应详细描述。可能的界面反应，如扩散，混合晶体的形成，和钝化层的去除应通过电子显微镜和高分辨率光谱确认。最后，建立了Al / Ti复合材料超声焊接的连接模型。

Hybrid lightweight design dominates the development of future vehicle concepts in traffic engineering and the aerospace industry. To realize such multi-material systems appropriate and effective joining technologies are necessary. In this project ultrasonic metal welding will be investigated to realize aluminum-titanium hybrid joints in the solid state. Important structural aluminum and titanium alloys were chosen to produce high strength joints by using advanced process control and new welding tools. To identify the best process variant for structural applications a direct comparison of ultrasonic spot and torsion welding technique will be studied. Detailed experiments to the kinematics during ultrasonic welding are central points of interest, which are examined by laser vibrometry online. The process parameters welding force, oscillation amplitude and welding energy are determined by using modern statistical methods for the design of experiments. The bonding phenomena are related to the process variant and its specific process parameters and should be described in detail. Possible interfacial reactions like diffusion, formation of mixed crystals, and removal of passivation layers should be confirmed by electron microscopy and high-resolution spectroscopy. Finally a bonding model for ultrasonic welding of Al / Ti hybrids should be developed.