Microstructure and mechanical performance of AZ31/2024 dissimilar alloy joints using a multi-interlayer of Ni/Al/Zn via ultrasonic-assisted transient liquid phase bonding

Here, the novel combination of multi-interlayers composed of Ni, Al, and Zn foil was used to join AZ31/2024 dissimilar alloys via ultrasonic-assisted transient liquid phase bonding (U-TLP) in air condition. This multi-interlayer acts as a 'physical barrier' to forbid the formation of Mg-Al Intermetallic compounds (IMCs) and engineer IMCs to improve the mechanical performance. The function of the Al interlayer is to form Al-Ni and Al-Mg-Zn products and reduce the excess dissolution of AZ31. Results show that adopting Al/Zn/Ni/Zn multi-interlayer helped to form a mixed IMCs layer composed of Mg2Ni, Al3Ni, Al3Ni2, and AlMg4Zn11 to enhance the bonding between Ni interlayer and AZ31, which prohibits the lack of bonding using Zn/Ni/Zn multi-interlayer. The shear strength of the joints using Al/Zn/Ni/Zn multi-interlayer has been up to 95.3 MPa from 35.2 MPa with Zn/Ni/Zn multiinterlayer. The role of Al interlayer played during U-TLP bonding was discussed in detail, and the evolution of microstructure on both sides of the Ni interlayer was analyzed. (c) 2020 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

A novel combination of multi-interlayers composed of Ni, Al, and Zn foil was used to join dissimilar alloys, resulting in enhanced shear strength and improved mechanical performance. The Al interlayer played a crucial role in forming mixed IMCs layer, enhancing bonding between Ni interlayer and AZ31.