Effect Of Inoculation On The Microstructures And Mechanical Properties Of Magnesium Alloys Spot Welding

With the increasing depletion of energy,the demand for light weight of industrial products such as aerospace,rail transportation,automobile production is increasing.Magnesium is the lightest metal in engineering materials.In this paper,the microstructure and grain size of the welding head in the resistance spot welding process of magnesium alloy is studied.The microstructure of magnesium alloy welded joint is refined and the mechanical properties of the welded joints are refined by adding three kinds of inoculation(SiC,La,Ti).The experimental results show that the grain size of the welding nugget region in the center of the spot welding is a lot of equiaxed dendritic crystal in the center of the spot welding of 3.0 mg Ti particles,the average grain size of the heat affected zone is about 35~45 ?m,and the shear force is 2.11 kN.When the SiC is added as the inoculation,the effect of the content of 1.0 mg on the refinement of the spot welding is the most obvious,and the the center of the welding region is composed of a large number of other grains,the maximum tensile force is 2.15 kN and the shear force increased by 22.8%.When the La is added at 3.0 mg,the number of the grains in the columnar dendrites is highest,the maximum shear force is 2.25 kN,which increased by 28.6%.And the shear strength increased with the increase of the content of the inoculation.