Effect of Harmonic Vibration on Microstructure and Mechanical Properties of AA5083-H321 Aluminum Alloy GMAWWelds

In this research, the effect of vibration at the resonant range (75 Hz) on the hardness and tensile strength of AA5083- H321 aluminum alloy, were welded by gas metal arc welding (GMAW) investigated. Vibration forces were ranged from 850 N to 2200 N, under identical welding parameters. Tensile strength and hardness testing of welded samples were performed. After mechanical tests, the fracture surfaces of welds were examined using scanning electron microscope (SEM) and discussed. The results showed that with increasing vibration force, the tensile strength and fracture strength of the specimens were welded during vibration, were increased by about 3 and 9 percent, respectively, compared to the non-vibrated weld sample. However, no significant change was observed in the hardness of the welded specimens. Mean grains size and heat affected zone of the sample was welded was welded with conventional GMAW, were about 200 μm and 1800 μm, but due to inducing vibration, as vibration force increased from 850 N to N 2200 N, Mean grains size was reduced to about 75 μm and HAZ was reduced from about 1000 μm to 700 μm, that is, about 44 to 61%.