Selection of Constitutive Models for As-Cast Low Alloyed Al-xSi-yCu Alloys

To guarantee the computational accuracy of the finite element model, the strain-compensated Arrhenius-type model, modified Fields-Backofen (m-FB) model and modified Zerilli-Armstrong (m-ZA) model were established to predict the high-temperature flow stress of as-cast low alloyed Al-0.5Cu, Al-1Si, and Al-1Si-0.5Cu. To determine the material constants of these three constitutive models, isothermal compression tests of the three aluminum alloys were carried out on a Gleeble-3800 thermal simulator. The prediction results of the constitutive model were compared with the experimental results to evaluate the prediction accuracy of the constitutive models, and to provide a basis for selecting the most suitable constitutive models (parameters) for the three alloys mentioned above. It is found that the strain-compensated Arrhenius model and m-ZA model can be regarded as the most suitable constitutive models for Al-0.5Cu and Al-1Si alloys, respectively, and these two constitutive models also can be applied to Al-1Si-0.5Cu alloy. However, the m-FB model can be applied to Al-0.5Cu, Al-1Si and Al-1Si-0.5Cu alloys only under high temperature and medium strain conditions.