Analysis of deformation inhomogeneity and slip mode of TA15 titanium alloy sheets during the hot tensile process based on crystal plasticity model

Understanding of the deformation inhomogeneity and slip mode of titanium alloys during the thermo-mechanical process is crucial for effectively guiding the forming process and controlling the property of final products. To this end, a crystal plasticity finite element model (CPFEM) was proposed to address these issues of polycrystalline TA15 titanium alloy sheets during the hot tensile process along the rolling direction (RD) at 750 degrees C in this paper. Based on the analysis of Schmid factors (SFs), the weighted averaged SF of basal and prismatic slip systems (WABPSF) was adopted as the criterion of 'soft' or'hard' grains. In term of the simulated results, the localized stress concentration tends to spread at the parts of hard grains adjacent to soft grains, yet the distributions of strain manifest in a sequential fashion. As for the slip mode of TA15 rolling sheets during the hot tensile process along RD, multiple slip systems can be activated as long as the resolved shear stress is larger than the critical resolved shear stress (CRSS). And the prismatic slip systems act as the predominant slip mode, and exhibit an incremental role on the tensile deformation along RD. Meanwhile, the simulated results indicate that the activation of basal slip systems would result in the distinct reduction of basal SF.