Article ID Journal Published Year Pages File Type
830569 Materials & Design (1980-2015) 2012 10 Pages PDF
Abstract

The relatively new welding process friction stir welding (FSW) was applied in this research work to join 6 mm thick dissimilar aluminum alloys AA5083-H111 and AA6351-T6. The effect of tool rotational speed and pin profile on the microstructure and tensile strength of the joints were studied. Dissimilar joints were made using three different tool rotational speeds of 600 rpm, 950 rpm and 1300 rpm and five different tool pin profiles of straight square (SS), straight hexagon (SH), straight octagon (SO), tapered square (TS), and tapered octagon (TO). Three different regions namely unmixed region, mechanically mixed region and mixed flow region were observed in the weld zone. The tool rotational speed and pin profile considerably influenced the microstructure and tensile strength of the joints. The joint which was fabricated using tool rotational speed of 950 rpm and straight square pin profile yielded highest tensile strength of 273 MPa. The two process parameters affected the joint strength due to variations in material flow behavior, loss of cold work in the HAZ of AA5083 side, dissolution and over aging of precipitates of AA6351 side and formation of macroscopic defects in the weld zone.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Dissimilar friction stir welding of AA5083-H111 and AA6351-T6. ► Tool rotational speed and pin profile affect weld microstructure. ► Weld zone exhibits three kinds of microstructures. ► Material flow behavior during welding influences tensile strength.

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Physical Sciences and Engineering Engineering Engineering (General)
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