A study on the mechanical characterization of friction stir welds between aluminium alloys 6061-T6 and 6082-T6 was carried out. For comparison, single alloy joints made from each one of the two alloys were also performed. The work included microstructure examination, microhardness tests, tensile tests and bending tests of all joint types. An approximate finite element model of the joint, taking into account the spatial dependence of the tensile strength properties, was made, modelling a bending test of the weldments.