Hardness Prediction of AA 2024-T3 FSW Weld

The hardness of AA 2024 is mainly dependent of the precipitation state in the material. This one will vary through the process of friction stir welding (FSW) which generates heat and deformations. The most important effect will be the thermal excursion which greatly affects the nature and the distribution of precipitates and so the mechanical properties of the material. Three Myhr & Grong-type submodels have been used in this study in order to simulate the variation of hardness in AA 2024-T3 FSW welds. These models allowed to simulate the hardening by growth of S-precipitates and the softening by coarsening and dissolution of GPB zones / co-clusters or S-precipitates. Finally, the natural ageing was taken into account following the Robson model. The complete model has been calibrated with isothermal data found in the literature and still has to be optimised. Nevertheless, preliminary results show the coherence of the model when performed on isothermal data. The model has been also applied to predict FSW hardness profiles that are compared to those found in the literature.