Experimental and numerical multi-scale investigation on the efficiency of FSW for dissimilar aluminum alloys
Résumé
In this presentation, an experimental and numerical analysis of joints made by FSW is proposed for dissimilar aluminium assemblies. In a first part, the presentation focuses on the scale of onion rings to highlight crystallographic texture and subsequently mechanical heterogeneities. OHR-DIC photomechanic analyses aimed to document the banded heterogeneous response of a 2024/2198 dissimilar joint. The material mixture is then simulated with the Coupled-Eulerian-Lagrangian finite element method to observe the composition heterogeneities for a joint produced with a trigonal pin. In a second part, the work proposed focuses on macroscopic scale through a welded cross section. OHR-DIC photomechanic investigations make it possible to observe the distribution of the strains through a joint composed of 7020 and 2139 aluminium alloys. The local mechanical behaviours are observed across the joint by means of tensile tests until failure. In addition, a thermo-mechanical finite element model has been developed to compute thermal kinetics during welding. This numerical model can predict the location of the breaking zone and its evolution according to the welding velocity and the tool rotation speed.