Microstructure and mechanical properties of TIG/A-TIG welded AZ61/ZK60 magnesium alloy joints
(1. School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105, China;
2. Hunan Provincial Key Laboratory of Vehicle Power and Transmission System, Hunan Institute of Engineering, Xiangtan 411104, China;
3. National Engineering Research Center for Magnesium Alloys, College of Material Science and Engineering, Chongqing University, Chongqing 400044, China)
2. Hunan Provincial Key Laboratory of Vehicle Power and Transmission System, Hunan Institute of Engineering, Xiangtan 411104, China;
3. National Engineering Research Center for Magnesium Alloys, College of Material Science and Engineering, Chongqing University, Chongqing 400044, China)
Abstract: The dissimilar joints of AZ61 and ZK60 magnesium alloys were obtained by tungsten inert gas arc (TIG) welding and activating tungsten inert gas arc (A-TIG) welding processes. Microstructure characterization shows that, the fine α-Mg equiaxed dendrite crystals contained Mg17Al12 and MgZn2 particles in the fusion zone. The average size of the α-Mg grains in the fusion zone was refined to 19 μm at welding current of 80 A, which resulted in the largest tensile strength of 207 MPa. The tensile strength and the width of the beam of the A-TIG welded AZ61/ZK60 joints showed strong dependence on the amount of TiO2. However, the inhomogeneity of the heat-affected zone near different base metals presented no significant effect on the mechanical properties of the welded joint.
Key words: AZ61; ZK60; dissimilar joints; tungsten inert gas arc (TIG) welding; activating tungsten inert gas arc (A-TIG) welding; inhomogeneity