Study On Microstructure And Mechanical Properties Of Welded Magnesium Alloys

It has become a higher request for weight saving and recycle of materials to reduce the energy consumption and pollution with the rapid development of aerospace, automobile and electron industries. Magnesium alloys, the lightest structural material, have many advantages such as high strength ratio, good castability, high damping capacity and recycleable characteristic, which are praised as the most potential materials to achieve weight saving and recycle. They have been attracting increasing interest. Society's demands promote basic theory research and production technical level of magnesium alloys, then promote the applications of magnesium alloys in industry fields. The application of any advanced material not only depends on its own properties, but also relies on the technologies of material manufacturing. Besides, manufacturing techniques such as welding and joining play an important role in exploiting the new fields of applications. It is difficult to bond magnesium parts, because magnesium alloys are extremely easy to form the oxide film. Furthermore, during welding there are also pore and crack, which reduce the mechanical properties of welded joints. However, up to now, the information on welding metallurgy, weldability and welding process of magnesium alloys is still limited, and many welding theoretics and technologies of magnesium alloys have not been solved. It has become one of main problems for welding of magnesium alloys.Effects of weld composition and welding parameters on microstructures and mechanical properties of tungsten inert gas (TIG) and metel inert gas (MIG) welded magnesium alloy joints have been investigated. Microstructures and compositions of the joints were investigated by optical and scanning electron microscopy (SEM) equipped with energy-dispersive spectrometer (EDS), X-ray diffraction (XRD) and an image analysis system. Besides, the characteristics of weld crack have been investigated. By analyzing the experimental data, some conclusions have been drawn as follows:...