Microstructure evolution and deformation mechanism of industrial pure titanium TA2 roll forming process

At room temperature， the predominant plastic deformation mechanisms in industrial pure titanium TA2 encompass dislocation slip， twinning， and interfacial interactions. This study combines mechanical analysis performed during roll-forming experiments and utilizes electron backscatter diffraction and optical microscopy to investigate the microscale deformation mechanisms on both the inner and outer surfaces of TA2 sheets during roll forming from 0° to 30°.The research results demonstrate that during the forming process， as the bending angle reaches 20°， a differential stress is exerted on the axis of the hexagonal close-packed structure on the inner and outer sides. On the inner side， the plastic deformation mechanism shifts from the previously dominant pyramidal slip and basal slip to mainly ｛1012｝ tension twinning， which is due to the distinct stress acting on the axis. On the outer side， where the axis is under compressive stress， dislocation slip remains the primary deformation mechanism because the occurrence of ｛1122｝ compression twinning is hindered by its high critical resolved shear stress and the fine-grained nature of the material. As a result， ｛1122｝ compression twinning functions as an auxiliary deformation mechanism on the outer side. These findings offer critical insights into the plastic deformation behavior of TA2 during the roll-forming process.