The Microstructure and Properties of TIG Welded Joint of AZ31B/Cu Dissimilar Metal

Abstract:

AZ31B magnesium alloy and T2 Cu metal plates with the thickness of 2mm were bonded by argon tungsten arc welding (TIG) under the conditions that the welding current is 100A and the welding speed is 150 mm/min. The microstructure, phase composition and properties of welded joint were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), micro-hardness test. The results show that AZ31B magnesium alloy and T2 Cu combined well with no cracks, porosities, incomplete penetration and other metallurgical defects. A transition zone composed of equiaxed and columnar crystals of α-Cu exists between the weld metal and base metal Cu, its width is about 80μm. The central area of the weld is made up of α-Mg matrix and Mg-Cu eutectic. The joint consists of α-Cu, α-Mg, Cu₂Mg, Mg₂Cu and little MgO, CuO phase. The micro-hardness of weld zone is significantly higher than that of the base metals, and its heat affected zone appears softening phenomenon.

• Periodical: Advanced Materials Research (Volumes 941-944)
• Pages: 2047-2052
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.941-944.2047
• Online since: June 2014
• Authors: Shuang Ming Du, Jie Hu, Tian Lan
• Keywords: AZ31B/Cu Dissimilar Materials, Joint, Microstructure, Property, TIG Welding

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