Dry sliding wear behavior study on friction stir weld joints of dissimilar aluminum alloys

Abstract

Friction stir welding (FSW) is a comparatively new emerging solid state nature welding process used for joining the various similar and dissimilar metals which were difficult to use in conventional welding. It has better mechanical properties in comparison with other welding process in the Weld zone. The aim of present work is to select the combinations of parameters for sound weld joints by friction stir welding technology of two different aluminum alloys; AA6101-T6 and AA6351-T6 of 6 mm plate thickness. Rotational speed of tool, Welding speed of tool, tilt angle of tool and axially downward force are the important combinations of process parameters. A computerized FSW machine has been employed for execution of the Welding process. The weld parameters have been used to fabricate four different joints to study their effect on wear property of joints. Optical microscopy has been carried out to study microstructural features of sound weld joints. Wear tests were performed on pin on disc machine to study the dry sliding wear behavior of weld joints. The wear test samples of the required dimensions have been cut from the nugget zone of weld joints. Scanning electron microscope (SEM) and Energy dispersive x-ray spectroscopy (EDS) analysis for compositional information for base metals and worn out surface of wear test samples of Friction stir welded dissimilar butt joints. It has been of observed that the wear rate of the base metal is lower than the friction stir welded joints. Presence of silicon content plays an important role in improving the wear resistance property of base metals. Wear properties of FSW joints were comparatively more than the base metals. Worn surfaces analysis reveal the formation of the grooves, scratches and wears debris, delamination and their combinations are the dominant mechanisms involve during material removal on sliding.