Multiscale study of texture evolution and slip competition in Ti65 alloy thin sheets under different loading paths

Near-α titanium alloy sheets are susceptible to localized failure during complex forming processes, primarily due to their strong initial textures. Elucidating the evolution mechanisms of such strong textures and the competing behaviors of slip systems under varying stress states is crucial for overcoming current bottlenecks in complex forming. In this study, the distinct deformation behaviors of Ti65 alloy sheets subjected to uniaxial tension and three-point bending were systematically investigated by combining experimental characterizations with Abaqus-VPSC multiscale simulations. The results demonstrate that under uniform tensile loading, the mechanical anisotropy is mainly governed by the dependence of the Schmid factor on the initial crystallographic orientation. Deformation is predominantly accommodated by prismatic <a> slip, resulting in texture feature stability. Conversely, the geometric constraints and strain gradients introduced during bending deformation increase the activation tendency of pyramidal <c + a> slip to accommodate the c-axis deformation of grains. This transition in the dominant slip mode is evident on the extrados of the bent sheet, reducing the stability of the initial texture. Furthermore, the crystal plasticity parameters calibrated using uniaxial tensile data reasonably predicted the heterogeneous deformation characteristics on the intrados and extrados of the bent sheet. This study provides an important theoretical basis for texture control during the forming of complex titanium alloy components.