Microstructure Prediction of Hot-Deformed Aluminium Alloys

In this paper, a deformation test method to reproduce, on a laboratory scale, the microstructure evolution of aluminium alloys occurring during industrial forming processes with a limited number of tests is presented. A hot inverse extrusion setup was designed in order to generate, inside one single specimen, a wide range of strains at a given temperature and ram speed. Two commercial aluminium alloys (AA6060 and AA6082) were investigated at different processing conditions (temperatures and forming rates). Detailed optical microstructures were examined and grain sizes were determined at different spots of each specimen. Thermo-mechanical coupled simulations of the deformation tests were performed using the DEFORM 3D FEM code. On the basis of recrystallization equations, the distributions of strains, strain rates and temperatures were correlated to the grain sizes measured through linear regression. Finally, FEM simulations were run again with the established recrystallization model, and the results were compared with the experimental data.