Numerical and experimental investigation of deformation behavior of a duplex microstructure of a g-TiAl alloy using crystal plasticity and two scale modeling approach

Abstract

The 3-dimensional microstructure of a duplex g-TiAl has been modeled in a parameterized FE-model using a two scale approach (FE2-approach) for micro and macro coupling. The most important microstructural features, such as a2 and g-phases, their volume percents, orientations, lamellar and globular arrangements, were representatively incorporated. The microstructure information was experimentally determined by SEM, TEM and EBSD analysis. For describing the micromechanics of the phases a continuum based crystal plasticity model was used. The model parameters were validated on the microscopic level by nano-indentation testing and on the macroscopic level by tensile tests at room temperature. The global deformation behavior was explained fairly well by the slip interactions, the local stresses, and the local strains predicted by the modeling approach. The model can be used for optimizing the microstructure of polycrystalline materials for components.