Influence of Traverse Speed in Self-Reacting FSW of AA6061-T6

Self-reacting friction stir welding (SRFSW) is a variant of friction stir welding in which a small modification of the tool design, i.e., the addition of a lower shoulder eliminates the need for a backing plate. In the present work, SRFSW was carried out on 4-mm-thick AA6061-T6 aluminum, which is one of the most extensively used of the 6000 series aluminum alloy at different traverse speeds. The focus of this research work is to understand the effect of tool traverse speed on the mechanical properties and the microstructural zones created in the joints, keeping all other parameters constant. From the tensile test, it was observed that the yield strength and tensile strength of the joints increased with the increase in traverse speed. From the fractography study, ductility was found to increase with the increase in traverse speed. From the Vickers microhardness test, it was clear that the hardness distribution across the thickness indicated uniformity in mechanical properties across the thickness. From the microstructural study, it was observed that with the increase in welding traverse speed, the elliptical swirl zone size and shape changed significantly, which affects the joint quality significantly. It was also observed that traverse speed has significant effect on the flashing out of material from weld zone. With lower traverse speed, chances of flashing out of material is more, which results in the formation of wormhole defect (main weld defect in friction stir welding). A saddle-shaped macrostructure of the bobbin tool friction stir welding joint was observed, which was prominent in the advancing side and was found to have a banded microstructure.

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  • English

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  • Accession Number: 01700348
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Feb 13 2019 10:25AM