Investigation on the Role of Al<sub>2</sub>O<sub>3</sub> Nanoparticles in Enhancing Nugget Zone Properties during Friction Stir Welding

Nano particles are used to enhance the strength of the surface when mixed with appropriate ratio. In this work, metal matrix based surface nanocomposite is attempted through Friction stir welding (FSW) process. FSW is a type of solid-state welding process does not involve any chemical reaction, melting, secondary phase formation and also microstructure-controlled welding process. FSW process is performed on AA 2024 and AA 7075 aluminum alloys when filled with nano Al<sub>2</sub>O<sub>3</sub> in the nugget zone. In this regard, micro hole is introduced before welding on the nugget zone for filling of nanoparticle addition. Process parameters considered are weight % of nanoparticle, tool rotation speed, and welding speed. Response parameters considered are tensile strength and bending strength. Taguchi L<sub>9</sub> experimental steps are followed to perform the experiments. The result of the experiment is realized that surface nanocomposite is developed by varying the weight percentage of nanoparticle to the welding zone. The result of the experiment is understood that nanopowder addition is used to enhance the strength. The better strength is noticed with 2% nano particle due to proper stir action and material mixing. Process parameters are significantly influence the strength of the welded sample. FSW process is easiest method to produce surface nanocomposite with better strength.