Experimental Investigations on Effect of Tool Welding Speed on Microstructure and Tensile Properties of FSW Dissimilar Joints Reinforced with Sic Nanoparticles

Abstract

Aluminum alloy plates of 2024-T351 and 7075-T651 reinforced with nano-sized particles of silicon carbide (SiCNP) in the groove cut of the rectangular shape made on the adjoining surfaces of the plates and are welded in the butt–joint combination using friction stir welding (FSW) technique. FSW tool of shape taper threaded cylindrical is employed to produce composite at the weld nugget zone (WNZ) of the FSW dissimilar joint. During FSW, the dissimilar aluminum alloy plates were welded by varying the tool welding 232speed (TWS) from 20 to 200 mm/min, while the tool rotation speed (TRS) and tool plunge depth (TPD) were kept at a constant of 1000 rpm and 6.20 mm, respectively. The effectiveness of varying the TWS on the SiCNP distribution in the WNZ of the joint specimens is investigated by conducting microstructure analyses using optical microscopy and scanning electron microscopy. The tensile tests for the FSW joint specimens reinforced with SiCNP at the WNZ are conducted, and the weld joint strength is investigated. The results indicated that FSW dissimilar joint produced for TWS range 40–50 mm/min with constant TRS of 1000 rpm and TPD of 6.20 mm results in the higher weld joint tensile properties, observes a defect-free and uniform distribution of SiCNP at the WNZ. Increasing the TWS above 75 mm/min results in SiCNP being stretched toward the retreating side of the weld region and improper distribution of SiCNP.