Welding, Joining and Additive Manufacturing International Conference 2015

Ultrasonic additive manufacturing (UAM) is a solid state processing technique that uses ultrasonic vibrations to join metal tapes into near net-shaped components. Majority of published research focuses on processing parameter optimization to eliminate macroscopic void formation at the interfaces. Current research focused on measurements of thermal transients, high-resolution characterization of interface regions, and extension of the technique to join high-temperature alloys including copper. Thermal transient measurements show complex energy dissipation across the tape interfaces. High-resolution characterizations indicate a bonding mechanism due to localized plastic deformation of asperities that undergo recrystallization and grain growth across the interface. Evidence for localized solidification microstructures, generated due to frictional sliding between the sonotrode and the tape material, is also seen. Similar mechanisms were also observed during joining of copper alloy sheets joined by application of higher power levels. Potential application of the above processing to develop hybrid materials with embedded sensors will be discussed.