Microstructure and Mechanical Properties of Mg₉₆Zn₂Y₂ Joints Welded by Resistance Spot Welding

Abstract:

Mg₉₆Zn₂Y₂ is widely studied due to its high tensile yield strength and elongation. These excellent properties were considered to relate to the nanostructure of the alloy such as fine-grained α-Mg matrix and bent long period stacking ordered (LPSO) structure. In order to extend the application of this Mg alloy, development of the welding technique is indispensable. In the light of the reliability and productivity, resistance spot welding is an attractive method to join this Mg alloy. In this study, we joined the Mg alloys by the resistance spot welding with cover plates. Mechanical properties and structures of the nugget of the joints were investigated. In the case of the joints welded with cover plates, the welded region of the Mg alloy sheets were covered with steel plates to supply adequate heat for welding. Joints of extruded Mg₉₆Zn₂Y₂ were obtained at relatively low welding current. The tensile strength of Mg₉₆Zn₂Y₂ alloy was higher than that of the commercial Mg alloy AZ31B joints. Mg₉₆Zn₂Y₂ base alloy had extended LPSO phase along extruded direction in α-Mg grains. At the nugget, net-like secondary phase was produced in the Mg grains. The relationship between the microstructure in the joints and mechanical properties were discussed.

• Periodical: Materials Science Forum (Volumes 706-709)
• Pages: 1187-1192
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.706-709.1187
• Online since: January 2012
• Authors: Chihiro Iwamoto, Shinobu Satonaka, Yoshihito Kawamura
• Keywords: HRTEM, Interface, Resistance Sport Welding, Transmission Electron Microscopy (TEM)

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