Abstract
Tungsten inert gas (TIG) arc welding of 2219 aluminum alloy was assisted with a trailing periodic ultrasonic vibration, which was output from a trailing roller behind the welding torch. It was found that the weld appearance was periodically convex due to the periodic input of ultrasonic vibration. With the addition of ultrasonic vibration, the columnar grains in the weld zone transformed to equiaxed grains, so along the longitudinal direction, the equiaxed grains and the columnar grains were alternately distributed due to the periodic ultrasonic vibration. The effects of different ultrasonic powers were investigated. The penetration depth and the amount of the melting metal both increased as the ultrasonic power increased. The coarse precipitated phases in the weld zone tended to disperse uniformly under ultrasonic vibration. Compared with conventional TIG welded joints, the hardness of the weld zone of the ultrasonic assisted TIG welding increased by 8.43%, and the tensile strength increased by 29.02%. The ultrasonic cavitation could decrease the nucleation radius and break the dendrites, which led to the grains’ refinement and the final mechanical properties’ improvement.
Highlights
Tungsten inert gas (TIG) arc welding is one of the most frequently used welding methods for aluminum alloys
Zhang et al [2] investigated the effects of the high energy ultrasonic field on the microstructures and mechanical properties of A356 alloy, and it was found that the long dendritic silicon phases were broken into pieces and that considerable improvements of the mechanical properties were achieved due to the ultrasonic treatment
Hu et al [3] proposed ultrasonic assisted friction stir welding (FSW) for 2219-T6 aluminum alloy, during which ultrasonic vibration acted on the bottom surface of workpieces
Summary
Tungsten inert gas (TIG) arc welding is one of the most frequently used welding methods for aluminum alloys. Based on the applications of ultrasonic vibration in casting, ultrasonic energy has been used in many welding methods. Hu et al [3] proposed ultrasonic assisted friction stir welding (FSW) for 2219-T6 aluminum alloy, during which ultrasonic vibration acted on the bottom surface of workpieces. TIG welding for aluminum introduced ultrasonic vibration directly on theonworkpiece duringduring. Welding molten pool through the introduced ultrasonic vibration into the gas metal arc (GMA). Based on the acoustic radiation force, a method of wire and found that the grain size decreased. Based on the acoustic radiation force, a method of adding adding coaxial ultrasonic vibration in arc welding was proposed byal.Sun al.Fan [8] and et al.The [9,10].
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