Mechanical Properties and Microstructures of Welded Joints of Mg Alloy by Electron Beam Welding

MB2 alloy was welded by electron beam welding,the effects of welding parameters on the depth-to-width ratio of weld seam,mechanical properties and microstructure of the welded joint were studied.The results show that focal position and scanning graph can deeply affect the depth-to-width ratio of welded joints.The good joints without defects,such as crack and gas pore,can be welded by round scanning graph,2000 Hz scanning frequency and defocus.The microstructure in weld seam is single fine equiaxle crystal and the maximal tensile strength of the welded joint is 235MPa,up to 92% of base metal.