Effect of Cu content on properties of Cu/Zn+15%SAC0307 +xCu/Al joint by ultrasonic excitation at low temperature

Abstract The ultrasonic-assisted soldering joint of Cu/Al with different contents of copper particles added to solder powder at low temperature was studied. In this study, 15%SAC0307 solder powder with a diameter of 500nm, different amounts copper particles with a diameter of 500nm were mixed with zinc particles of a diameter of 45μm to fill the Cu/Al joint, and the soldered was heated to 240°C for ultrasonic-assisted under the environmental atmosphere. Successfully achieved micro-joining of Cu/Al under ultrasonic-assisted at low-temperature. The results have shown that, when the copper content was 0%-15%, two layers of complete and continuous CuxZny compounds were formed at the copper side interface. When the copper content was more than 15%, the IMC layer of the copper side interface was not obvious, and a large amount of CuxZny compounds were formed near the copper side. The base metals on the aluminum side formed a solid solution combination with zinc. When the addition amount of copper powder was 15%, the soldering seam was smooth and flat, the defect between balls was not obvious, and the IMC was uniformly distributed, so the average shear strength reached the maximum value of 47.37MPa.