Research On Aluminum Alloy And Magnesium Alloy CMT Welding Technology

With setting energy conservation and reduction emission, The application of aluminum alloy and magnesium alloy is increasingly wide The meet of them is unavoidable in industrial application. It is easy to have cracks and intermetallic compound in weld joint. It is difficult to have good performance of weld joint. Cold metal transfer(CMT) technology can greatly decrease heat input. It will be significant in production if CMT technology can be used in high strength connect of magnesium and aluminum.1.5mm thickness of 6061 aluminum alloy and AZ31 B magnesium alloy are used by CMT technology. in this article. Firstly, weld magnesium and aluminum with AlSi5 in lap joint, explore the welding technology parameter, check the reasons of pore defects, crack and intermetallic compound. Secondly, weld magnesium and aluminum with AlSi5, AlSi12 and AlMg5 wire respectively with the assistance of the 0.1 mm thick zinc foil as interlayer, find out the joint with the highest mechanical properties and analyze the action of different alloy elements. Finally, with the assistance of the 0.1 mm thick zinc foil, analysis influence of mechanical properties and elements distribution to weld joint at different heat inputExperiment results showed that the pore and crack defects are easy to be formed in welding joint using AlSi5 welding wire, Mg-Al intermetallic compounds is generated in magnesium side fusion zone. Tensile fracture occurred in the magnesium side of the fusion zone, the fracture properties is brittle. Intermetallic compounds, such as Al12Mg17, AlMg and Al3Mg2 exit in the magenesium side fracture.. These compounds performance rigid and continuous distribution in magnesium side fusion zone and deteriorate mechanical properties of weld joints. On the basis of the first step, using AlSi5 wire, weld magnesium alloy and aluminum alloy under the assistance of 0.1 mm zinc foil, The width of the magnesium side of fusion increased. Mg-Zn intermetallic compounds is generated in the reaction in the welding process. Mg-Zn compounds and Mg-Al compounds are cross distributed in side the fusion zone To some extent, It prevent the cracks, The joint mechanical properties relative increased 30% than magnesium/aluminum welding directlyUsing AlSi12 and AlMg5 wire, weld magnesium alloy and aluminum alloy under the assistance of 0.1 mm zinc foil, MgZn2 and Al12Mg17 is generated in magnesium side fusion zone.when using AlMg5 wire The mechanical properties is almost the same as using AlSi5 wire. Mg2 Si, MgZn2 and Al12Mg17 is generated in magnesium side fusion zone.when using AlMg5 wire. The mechanical properties relative increased 30% than magnesium/aluminum welding with Zn interlayer. Tensile fracture occurred in the weld center zone. the fracture properties is brittle. The reason is pores defects generated in weld center zone. The presence of porosity greatly reduce the effective bearing area of the joint. The weld microstructure is compact and porosity defect is less when using AlSi12 wire in low heat input. Zinc loss seriously and pores increased in high heat input. It can deteriorate the mechanical properties of weld joint. Reasonable heat input can reduce the pores, cracks and intermetallic compounds, and can obtain high-quality welding joint.