GRAIN SHAPE EVOLUTION ANALYSIS IN THE EXTRUSION OF 6XXX ALLOYS BY USE OF A LAGRANGIAN FEM CODE

A unified model is developed to study the grain shape evolution of 6XXX aluminum alloys during deformation and consequent static recrystallization in hot metal forming processes. In this model, effects of grain dynamic recrystallization (following continuous and geometric dynamic recrystallizations theories) during deformation, of dislocation densities distribution, of stored energy and of consequent grain static recrystallization are considered. Developed model has been implemented in the langrangian FEM code Deform and validated over experimental trials performed at different forming temperatures and strain rates on a AA6060 aluminum alloy.