The influence of the friction stir welding conditions on weldability of two very popular aluminum alloys, in welding construction, is analyzed in this study. Non-heat-treatable (AA5083-H111) and a heat-treatable aluminum (AA7075-T651) alloy, are characterized by markedly different strengthening mechanisms and microstructural evolution at increasing temperatures. Dissimilar weldments were produced by the friction stir welding process under different welding conditions. The welding parameters were rotational speed, welding speed, tool geometryŁ material location and tool position. Their metallographic and mechanical properties were analyzed and compared using metallographic examination, hardness test and tensile test.
Dissimilar joints show some defects that differ due to the welding conditions. Higher rotational and welding combination speeds achieve sound joint associated with higher strength compared to the other welding joints. Moreover, when the soft material is located at the retreating side the weldment performance is improved.
Due to the relationship between metal formability and temperature, the heat distribution under various welding parameters was studied. The temperature analysis indicates that increasing the rotational speed increases the produced heat and consequently, the mixing efficiency of the welded alloys.