Characteristics of AZ31 Mg alloy joint using automatic TIG welding

• Published in: International journal of minerals, metallurgy and materials Vol. 24; no. 1; pp. 102 - 108
• Main Authors: Liu, Hong-tao, Zhou, Ji-xue, Zhao, Dong-qing, Liu, Yun-teng, Wu, Jian-hua, Yang, Yuan-sheng, Ma, Bai-chang, Zhuang, Hai-hua
• Format: Journal Article
• Language: English
• Published: Beijing University of Science and Technology Beijing 2017; Springer Nature B.V; Shandong Key Laboratory for High Strength Lightweight Metalic Materials, Advanced Materials Institute, Shandong Academy of Sciences, Jinan 250014, China%Shandong Engineering Research Center for Lightweight Automobiles Magnesium Aloys, Advanced Materials Institute, Shandong Academy of Sciences, Jinan 250014, China
• Subjects: Automatic welding; Basal plane; Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Composites; Corrosion and Coatings; Crystal lattices; Electron back scatter; Epitaxial growth; Friction stir welding; Gas tungsten arc welding; Gas welding; Glass; Grains; Heat affected zone; Inert gas welding; Lasers; Light microscopy; Magnesium alloys; Magnesium base alloys; Materials Science; Metallic Materials; Microhardness; Microstructure; Natural Materials; Optical microscopy; Rare gases; Recrystallization; Robots; Scanning electron microscopy; Spectrum analysis; Surfaces and Interfaces; Tensile properties; Texture; Thin Films; Tribology; Tungsten; Welded joints; Welding; X-ray spectroscopy; magnesium alloys; TIG welding; microhardness; microstructure; texture
• ISSN: 1674-4799; 1869-103X
• DOI: 10.1007/s12613-017-1383-8

The automatic tungsten-inert gas welding(ATIGW) of AZ31 Mg alloys was performed using a six-axis robot. The evolution of the microstructure and texture of the AZ31 auto-welded joints was studied by optical microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and electron backscatter diffraction. The ATIGW process resulted in coarse recrystallized grains in the heat affected zone(HAZ) and epitaxial growth of columnar grains in the fusion zone(FZ). Substantial changes of texture between the base material(BM) and the FZ were detected. The {0002} basal plane in the BM was largely parallel to the sheet rolling plane, whereas the c-axis of the crystal lattice in the FZ inclined approximately 25° with respect to the welding direction. The maximum pole density increased from 9.45 in the BM to 12.9 in the FZ. The microhardness distribution, tensile properties, and fracture features of the AZ31 auto-welded joints were also investigated.