Investigation on surface roughness, ultimate tensile strength, and microhardness of friction stir welded AA7075-T651 joint

Abstract

From the last two decades the application of Friction Stir Welding (FSW) process is increased in industry due to its advantages such as ecofriendly and improved mechanical properties over the metal inert gas welding and tungsten inert gas welding. In FSW joint is fabricated by the heat generated using rotating, non-consumable tool, whereas the material remains in solid state. In the present work, the mechanical behavior of Aluminum 7075-T651 alloy (AA7075-T651) FSW joints were investigated in terms of surface roughness, ultimate tensile strength (UTS), and microhardness. Investigations were carried out by varying the welding processes parameters, namely the tool rotation at 1000, 1400, and 2000 rpm, and at two levels of welding speed of 20 and 28 mm/min. FSW experiments were performed under dry conditions using a tool having conical pin geometry. Experimental investigations showed a higher value of UTS for FSW joints at tool rotation of 1400 rpm and welding speed of 20 mm/min. the higher value of microhardness and lowest surface roughness at weld bead was observed at lower tool rotation of 1000 rpm. This study suggests further works on the mechanical behavior of high strength AA7075-T651 FSW joint considering the effect of tool geometry and hybrid welding techniques.