Numerical predictions and experimental investigation of the temperature distribution of friction stir welded AA 5059 aluminium alloy joints

AA 5059 aluminium alloy is a material well suited for military applications because of its high strength to weight ratio and high toughness. Due to the high magnesium content, this material is frequently used in ship hull structure building because of its good corrosion resistance and good strength characteristics. Friction stir welding is a solid state welding process and it is a suitable method for joining nonferrous materials such as aluminium alloys. The objective of this work is to predict the temperature distribution in butt welding of AA 5059 aluminium alloy of 4 mm thick plates during friction stir welding. Numerical simulations were developed as a three dimensional, non-linear finite element model using COMSOL multi-physics to predict the complete thermal history of the welded specimens. Experimental work has also been carried out to explore the thermal history of a workpiece. The temperatures predicted numerically are compared to the experimental values in order to evaluate the joint performance and the weld zone characteristics. These results indicate that the values are in good agreement with each other.