| Abstract Scope |
Lightweight, multi-material body structures are essential for improving vehicle fuel economy and lowering carbon emissions. Demand for these material architectures especially 7xxx wrought aluminum, cast Al/Mg alloys, and advanced high-strength steels (AHSS) to replace mild steel and deliver weight reduction, recyclability, and crash-worthiness is increasing in the modern automotive industries. Conventional fusion welding, however, causes solidification cracking and porosity when these dissimilar alloys are joined.
Ultrasonic Spot Welding (USW) offers a solution: high-frequency vibrations generate interfacial frictional heat without melting, enabling fast and crack-free metallurgical bonds. This work optimizes key USW parameters to scale the process for joining different multi-material combinations, including Al/Cu thin-foils for multi-layers battery connections. The resulting guidelines improve joint strength and reliability, supporting next-generation of lightweight automotive architectures.
This project is funded by the U.S. Department of Energy, Vehicle Technology Offices, under Joining Core Program. |