Abstract
In the present contribution, a crystal plasticity-based model is presented which captures the yield stress of polysynthetically twinned crystals of TiAl from room temperature up to elevated temperatures around 900°C. In this temperature range, the temperature dependence of material parameters as well as the coupling between thermal and mechanical quantities have to be considered. While the latter is known from standard thermodynamic arguments, it is not straight forward to sufficiently capture the temperature dependent behavior of polysynthetically twinned crystals in the parameters of the constitutive model. A respective set of temperature-dependent model parameters has to consider the influence of different microstructural lengths within polysynthetically twinned crystals and has to account for the typical yield stress temperature anomaly, observed in intermetallic compounds. The here presented model captures the plastic anisotropy of a single polysynthetically twinned crystal as a function of temperature including the temperature anomaly and the microstructural strengthening by different phase boundaries. The simulation results are in good agreement with experiments from literature.
