Control of intermetallic compounds in Ultrasonic-Assisted Sn soldering of Mg/Al alloys

Magnesium and aluminum alloys are widely used in various industries because of their light weight and other properties. However, Mg-Al intermetallic compounds (IMCs) decrease the joint properties of Mg/Al, which limits its applications. Here, the alloys AZ31 Mg and 6061 Al are soldered together with Sn and Sn- 9Zn solders though different cooling rates via ultrasonic-assisted soldering to control IMC formation and growth. Results show that this prevents formation of Mg-Al IMCs such as Al3Mg2 and Al12Mg17; however, Mg2Sn forms in the soldered joints. The Mg2Sn thickness increases with soldering temperature, which reduces joint strength. The thickness is reduced using the Sn-9Zn solder, and the effect of Zn is analyzed. With the use of water-cooling, the Mg2Sn formation and growth are inhibited, the Mg2Sn thickness is kept below 5 lm, and the shear strength peaks at 53.2 MPa. A soldering model of Mg2Sn formation is pro-posed to reveal the evolution and inhibition mechanism of Mg2Sn. This study well controls IMC thickness and improves joint strength, thus expanding industrial application of Mg-Al dissimilar metals and pro-viding a feasible method for controlling IMCs in dissimilar metal joining.(c) 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Magnesium and aluminum alloys are widely used in various industries due to their light weight and other properties. However, the formation of Mg-Al intermetallic compounds (IMCs) reduces the joint properties, limiting their applications. This study successfully controls the IMC thickness and improves joint strength through ultrasonic-assisted soldering with different cooling rates, providing a feasible method for controlling IMCs in dissimilar metal joining.