Influence of Initial State on Forgeability and Microstructure Development of Magnesium Alloys

The paper is focused on magnesium alloys with different initial states – cast or extruded – for forging operations at the example of a wheel hub. The different initial microstructures have an influence on the deformation behaviour and therefore on the final mechanical properties of the components. The forming process of this component was designed with a numerical simulation tool (temperature of the billet, temperature of the die, velocity of the press ram), which need the sensitive material specific parameters for the description of the temperature depending deformation and recrystallization behaviour. All this parameters are necessary for a correct simulation of the whole process. The required parameters (flow stress, dynamic recrystallization kinetic) were determined in a deformation simulator. The models were developed considering preferentially the chemical composition of the AZ system. The content of aluminium is combined with the activation energy for the hot deformation process in the Zener-Hollomon parameter. After the experimental and numerical simulation the wheel hubs were forged on a 10 MN universal oil-hydraulic press at the Institute of Metal Forming for the validation of the laboratory results.