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2018
Conference Paper
Titel
New Developments in the Field of Ultrasound Enhanced Friction Stir Welding of Dissimilar Materials
Abstract
The field of hybrid versions of friction stir welding (FSW) is growing more and more over the last years. Several approaches are studied with the aim to improve the thickness of joints, the welding speed and the properties of dissimilar joints. The techniques of electrically, laser and gas tungsten arc welding assisted friction stir welding should be mentioned in this context. Further the method of ultrasound enhanced friction stir welding (USE-FSW) proved its positive influence on the resulting welds for similar aluminum/aluminum-joints and also on first dissimilar material combinations like aluminum/magnesium and aluminum/steel. Therefore this work will give an insight in the development of ultrasound enhanced friction stir welding on dissimilar joints of aluminum/steel and aluminum/magnesium. To get a comparison on the influence of the carbon content in steel the two different aluminum/steel joints of EN AW-6061/DC04 and EN AW-6061/C45 are investigated for conventional FSW and USE-FSW. Regarding the field of aluminum/magnesium-hybrid joints the combination of EN AC-48000/AZ91 is investigated with and without additional ultrasound. After optimizing the process parameter for each combination to achieve a maximum tensile strength by using design of experiment methods light microscopic investigations were carried out on the cross sections of the joints. Furthermore, tensile tests as well as nondestructive testing methods of X-ray radiography were carried out on the joints to analyze the joint quality of the welds. Additional corrosion examinations using scanning kelvin probe measurements, open circuit potential measurements and potentio dynamic polarization measurements completed the overview of the investigations on the different dissimilar joints.
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