Microstructure and mechanical performance of dissimilar material joints of 2024Al and SiO2 glass by ultrasonic assisted soldering with Cu interlayer

Ultrasonic assisted soldering was used to join SiO2 glass and 2024Al with Sn solder. The soldering temperature and pressure were set at 300 degrees C and 0.2 MPa respectively. The Sn solder had good wettability on the SiO2 glass surface by ultrasonic cavitation. At the same time, ultrasonic accelerated the dissolution of 2024Al in molten Sn solder. With the extension of ultrasonic time, Sn solder had better wettability on the surface of base material. The shear strength of the SiO2/Sn/2024Al joint was stabilized at 14-17 MPa by ultrasonic wetting for 5 min before soldering. Due to the large residual stress in the joint, the brittle fracture of the glass occurred during the shear process. To improve the load capacity of the joint, Cu interlayer was added to the joint to relieve the thermal stress. Cu foil effectively relieved the residual stress of the joint during the cooling process. Molten Sn solder reacted with Cu foil and formed intermetallic compounds (IMCs). IMCs effectively block the deformation of filler metal and reduce the generation of stress. When the ultrasonic assisted soldering time was 5 s, the SiO2/Sn/Cu/Sn/2024Al joint reached the highest shear strength about 28 MPa. (c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).