Effect of Vibration on Microstructure and Fatigue Properties of 6082 CMT-Welded Joints

In this paper, the effect of vibration on microstructure and mechanical properties of CMT weld is studied. The results show that in the vibration laser welding joint, the penetration depth and residual height of the joint increase, and the weld pores are suppressed. Analysis of the microstructure of the welded joint by optical microscope and scanning electron microscope shows that vibration can refine the grains and reduce the width of the heat-affected zone, which is conducive to the optimization of the mechanical properties of the welded joint. The residual stress test results show that after vibration is applied, the residual stress of the welded joint is reduced, which is related to the grain refinement. In fatigue experiments, the morphology of the fatigue fracture after vibration is more regular and smooth, and the spacing between fatigue stripes of 1 mm is smaller than the spacing of fatigue stripes without vibration (2 mm). The fatigue strength of the sample with a vibration frequency of 1222 Hz can reach 84.61% of BM. The application of vibration can improve the fatigue performance of welded joints.