The effect of friction stir processing on the friction stir welded AA1050-H14 and AA6082-T6 joints

Abstract

In this paper, the single-pass friction stir processing technique was applied to the friction stir welded dissimilar aluminium joints. This was done to create a comparative analysis of the mechanical properties of the friction stir processed FSW and unprocessed FSW welded joints of the AA1050-H14 and AA6082-T6 where different positioning (advancing and retreating) were used to assess which positioning gives better mechanical properties. A rotational speed of 1200 rpm, traversing speed of 40 mm/min and a tool tilt of 2° were used as for both friction stir welding and friction stir processing. The tests conducted include tensile tests, microstructure, microhardness. The fracture surfaces of tensile testing were further analysed using the scanning electron microscopes (SEM) with Oxford energy-dispersion spectrometry (EDS). The Ultimate tensile strength of 83.2 MPa, percentage elongation of 22.13% and yield strength 61.1 MPa were found on the friction stir processed joint. The friction stir processed joint also had a maximum microhardness of 80HV which was higher than that of the unprocessed one. The results show that FSP resulted in the improvement of the mechanical properties due to the grain size refinement. The positioning of aluminium alloy 1050-H14 on the advancing side and AA6082-T6 on the retreating side yielded better results for both unprocessed friction stir welded joints and friction stir processed joints.