PSI - Issue 17

Madhav Raturi et al. / Procedia Structural Integrity 17 (2019) 495–502 Madhav Raturi et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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zones. Despite choosing the favorable pin profiles, the process parameters can significantly affect the softening level and strength of the welded joints. The strength of the joints are influenced by the type of flow/mixing, sound and defect free weld nugget etc. as well as metallurgical aspects like grain size, presence of hardening precipitates etc. Thus, to obtain appreciable strength of different dissimilar friction stir welded joints, the judicial combination of process parameters is required which is an extensive exercise in itself.

(a)

(b)

Fig. 6. Macrographs of fractured surface; FE-SEM image and EDS mapping at fractured surface of AA6061-AA2014 dissimilar friction stir welded joints using TPZ pin profile at (a) 660 rpm tool rotation, 63 mm/min welding speed; (b) 900 rpm tool rotation, 63 mm/min welding speed.

4. Conclusions

In the present study on friction stir welding of AA6061-T6 to AA-2014-T6 by two different pin profiles was performed at different rotational speeds and welding speeds and their joint tensile strength, toughness and fracture behavior were studied. From the aforementioned experimental results, the following conclusions can be drawn: • Amidst different combinations of process parameters studied in the present work, the maximum tensile strength was obtained for joints made with TIF pin profile at tool rotational speed 1200 rpm and welding speed of 98 mm/min. TIF pin profile resulted in better mixing and sufficient heterogeneous coalescence was achieved with the balance heat input. The fracture location on the advancing side away from nugget zone testifies the strength capabilities of the weld nugget produced. • Joint prepared with TPZ pin profile with tool rotational speed of 900 rpm and welding speed of 63 mm/min resulted in maximum impact strength and also good tensile strength. A reasonably high elongation at failure was observed for joint prepared with TPZ tool pin at 660 rpm tool rotation and 36 mm/min welding speed.