Process optimization of high strength aluminum alloy TIG welding under vibration

Al-Cu-Mg high strength aluminum alloy was welded by semi-automatic TIG welding using Al-Si-based wire. During welding process, the mechanical vibration was applied. In order to optimize the process parameters, the orthogonal test was used. The tensile properties, hardness, microstructure and phase analysis were studied for different parameters of high strength aluminum alloy welded joint to research the interaction and mechanism of vibration. The results show that the optimum matching parameters are as follows, welding current I=110 A, the vibration amplitude D=0.05 mm, vibration frequency f=50 Hz. The performance at this time is that tensile strength R_m=289.68 MPa, elongation δ=4.95%, and the average hardness of the weld 108.0 HV. Vibration parameters can promote the formation of fine crystal axes, inhibit the production of porous defects. Suitable parameters vibration can refine the microstructure of the weld zone, inhibit the production of porous defects. The microstructure of the weld is mainly composed of fine equiaxed dendrite and cellular dendrite. So the comprehensive mechanical properties of welded joints will be improved.