Ductile damage modeling at elevated temperature applied to the cross wedge rolling of AA6082-T6 bars

Formability is one of the critical issues in metal forming processes since it is a limiting factor for the choice of the process parameters as well as for the attainable part quality. This issue is of even higher importance in processes carried out at elevated temperature, in which more variables are involved, and the temperature and strain rate changes can influence the material microstructural behavior, which, in turn, influences the fracture occurrence. In the paper, a modification of the Oyane–Sato fracture criterion providing the dependency on temper- ature and strain rate is proposed and applied to a cross wedge rolling process carried out on AA6082-T6 bars at elevated temperature. The modified fracture criterion was calibrated by means of hot tensile tests conducted at varying temperature and strain rate spanning the hot temperature range for the given alloy. Changes in the material formability were identified as a function of the testing parameters and also linked to the material microstructural characteristics. The fracture criterion was then implemented into the calibrated finite element model of the industrial process and validated by comparing the numerical and experimental outcomes.