Research on Microstructure and Fatigue Properties of Vibration-Assisted 5052 Aluminum Alloy Laser Welded Joints

Vibration-assisted laser welding experiment of 5052 aluminum alloys was carried out to focus on the influences of vibration parameters on microstructure and fatigue fracture. The experiment found that the vibration process homogenized the microstructure and promoted the formation of fine equiaxed grains significantly. In addition, vibration made the hardness uniform by reducing the area of the fusion zone. Experimental results of double welds showed that residual stress reduced by 58 to 77% under the action of micro-vibration. Vibration frequency and vibration acceleration had significant effects on the longitudinal and transverse residual stress, respectively. Under the same fatigue load condition, the average fatigue limits of the base metal (BM) and the welded joints were 160 and 120 MPa, respectively. Under the conditions of 10⁷ cycles, the maximum fatigue strength of the welded joints has reached 74.95% fatigue strength of the BM. Vibration-assisted laser welding could obviously improve the fatigue performance and increase the fatigue life of the welded joints, which was a potential way to improve the quality of welded joints.