Investigation of similar and dissimilar friction stir welding of aluminum alloys experimentally and numerically

Lightweight materials such as aluminum and magnesium alloys are increasinglyused in transportation industries. Physical and mechanical properties such ascorrosion resistance, low density and high formability are the most important factorsdetermining the wide spread use of a structural material. Friction Stir Welding(FSW) offers significant advantages for joining aluminum alloys and other lightweight materials. Some of these advantages are little distortion, low residual stressesand few weld defects. Because of the lower heat input and grain refinements, frictionstir welds in general have better mechanical properties such as the tensile strengthand fatigue life than the corresponding fusion welds for both heat treatable and nonheat-treatable aluminum alloys.In this study, the effect of welding parameters on the mechanical properties ofsimilar and dissimilar friction stir welded joints in AA6061 and AA7075 Al-alloysthin sheets are investigated. These parameters are the basic parameters such asrotational and transverse speeds of the pin. Additionally, three-dimensional nonlinearthermal and thermo-mechanical numerical analyses are performed. Stress andtemperature distributions in the weld region during the welding are determined usingthe Finite Element Method (FEM). APDL (ANSYS Parametric Design Language)code is developed to model moving heat source and change boundary conditions.The results obtained by the experiments and finite element analyses are presentedin tabular form and graphically. It is concluded that the performance of the weldedjoints AA6061 - AA6061, AA7075 - AA7075 and AA7075 - AA6061 Al-alloys canbe improved using the optimum welding parameters.Keywords: Aluminum Alloys, Friction Stir Welding, Finite Element Method.