Experimental Investigation on Refill Friction Stir Spot Welding Process of Aluminum Alloys

With the growing demand for lightweight reduction and environment protection, lightweight materials like aluminum and magnesium alloys have been widely applied in the automotive and aerospace industry. Being a solid state welding process, refill friction stir spot welding (RFSSW) is suitable for spot joining lightweight metals. In the present paper, the mechanical properties and microstructure of the RFSSW joints of 6061-T6 aluminum alloys were investigated. The influence of welding parameters, such as plunge depth, rotating speed and welding time, on tensile-shear strength was conducted through experiments. It is found that the tensile-shear strength is increased with the increase of plunge depth, rotating speed and welding time. And welding time is found to be an important key factor which affects welding quality. Research results can provide guidance for welding parameters optimization and welding quality promotion of RFSSW process of aluminum alloys.