NUMERICAL PREDICTION OF GRAIN SHAPE EVOLUTION DURING EXTRUSION OF AA6082 ALLOY

Extruded profiles applications require a strict control of the mechanical proprieties of the extrudates, in particular when undergoing severe loading conditions like in the transportation sector. Profile mechanical properties directly depend from its microstructure and texture, which are the result of multiple mechanisms based on precipitation mechanism or on grain shape evolution (grain refinement, recrystallizations, recovery and grain growth). In this direction the opportunity to predict the final profile microstructure under specific process parameters directly in the die design stage is of great relevance. The study involved experimental activity on grain size measurements during interrupted direct extrusion of an AA6082 round profile. The grain size measurements were coupled with the results of the simulation in order to regress analytical models based on effective strain, strain rate and temperature. Finally, the developed model was implemented in the numerical code through user subroutine so as to be used as microstructure prediction tool.