Powder bed based additive manufacturing processes allow the production of complex shaped components with nearly no waste of material. However, the mechanical properties of these materials are strongly influenced by the process and in many cases anisotropic. A crystal plasticity based simulation approach is used to predict the thermo-mechanical behaviour of IN718 generated by selective electron beam melting (SEBM).
For the full-field simulations, 3D unit cell models are built which represent the specific microstructure morphology as well as texture information. The microstructure information are a result either from EBSD measurements or from solidification and grain growth simulations using Cellular Automaton Lattice Boltzmann method. This work is part of the Clean Sky Joint Undertaken under Grant No. 32602 where a physically based simulation chain for the evolution of the microstructure and the mechanical properties of additive manufactured parts is developed. The grain growth simulations are part of this simulation chain and used as input to build the polycrystalline unit cell models. The interface between the two simulation approaches will be briefly described.
The crystal plasticity model used for the simulations is based on dislocation densities and includes a linear approach to model the temperature dependence of the elastic and plastic behaviour between room temperature and 650°C. Some material parameters used in the model are taken from literature while others are calibrated using inverse simulations of tensile tests at two different temperatures. After the calibration, the elastic and plastic behaviour at several temperatures and for different build-up directions is investigated and compared to experiments. The results show the capability of the approach to describe the effective mechanical behaviour.