Thermo-mechanical modelling of aluminium cast parts during solution treatment

The increasing interest of the automotive industry in reducing the weight of cars has resulted in increasing replacement of steel with aluminium parts as well as in an optimization of the design of the components, through structural analysis by FE-codes. The design and manufacturing of these components are important for the lifetime and reliability of the final parts. It is common practice to do load analyses in order to evaluate component lifetime and to do design optimization. However, in order to improve these structural analyses it is important to include the full load history of the material including the influence of the casting process and the subsequent solution treatment phase, quenching and artificial ageing. These manufacturing stages can have a high influence on the deformation and development of residual stresses which are important as initial conditions for subsequent load analysis during service. This paper presents a 3D numerical procedure capable of modelling the development of deformations and stresses from the full thermal history starting from mould filling through solidification to cooling and subsequent reheating for solution treatment, quenching and artificial ageing. However, in the present work the focus is on the modelling of the solution treatment only. The mechanical material model is described by a unified creep model to include rate effects and inelastic behaviour. An industrial component is used as an example to present the influence of creep at high temperature and calculated results with regard to deformations are compared with measurements.