中國有色金屬學報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 22 No. 6 June 2012 |
（1. State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China;
2. School of Materials Science and Engineering, Dalian University of Technology, Dalian 116085, China）
Abstract:Wrought magnesium alloy sheets were butt welded with gas metal arc welding process. Pores in the weld were investigated under different welding parameters, the causes of pore formation were systematically disposed, and the effects of porosity on the microstructure and mechanical properties of the joint were analyzed. The microstructure examination shows that the pores mainly appear close to the top or bottom part of the weld, and could connect to each other and lead to the formation of cracks in the welds. However, the pores can be controlled with proper welding parameters. The tensile testing results reveal that the average joint strength is close to or higher than that of the base metal. The microhardness in the weld can be even higher than that in the base metal due to the second phase strengthening of β-Mg17(Al, Zn)12 formed in the weld.
Key words: Mg alloy; gas metal arc welding; porosity; microstructure; second phase strengthening
