Ultrasonic Torsional Welding of Metal/Glass Ceramics Joints

Ultrasonic welding is a suitable solid-state joining technique for producing high strength joints of similar or dissimilar materials, even of material combinations that were previously considered as not weldable. Several varieties of transmitting the ultrasound into the joining partners exist whereas the investigated torsional welding principle utilizes a ring shaped sonotrode for transmitting ultrasonic vibrations tangentially to the welding force into the workpiece. Due to the specific sonotrode geometry ultrasonic torsional welding is a remarkably gentle welding technique, allowing to join even most sensitive components e.g. sensors or brittle elements. Nevertheless, ultrasonic torsional welded joints show high tensile strengths and helium-tightness. Current investigations focus on the realization of metal/glass ceramics joints. In this project two metals with different thermal expansion coefficients have been utilized as the metal joining partner. The glass joining partner was the commercially available Li 2 O-Al 2 O 3 -SiO 2 CERAN. For examining the microstructure light as well as scanning electron microscopy have been performed. Additionally, mechanical characterization has been carried out through tensile shear tests.