Effects of stress state on texture and microstructure in cold drawing-bulging of CP-Ti sheet
(State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China)
Abstract: Three different stress states of the combination of tensile (t) stress and compressive (c) stress, t-t, t-c and t-c-c, exist in the deformed commercially pure titanium (CP-Ti) sheet during cold drawing-bulging. The textures and microstructures in the different stress state regions were investigated by means of XRD and TEM analysis. Similar development of texture and microstructure is achieved with less thickness strain under multiaxial stresses in drawing-bulging than in cold rolling. The results show that texture and microstructure are much sensitive to multiaxial stresses. Twinning is more easily activated under compressive stress than tensile stress. Prism áa? slip is heavily affected by tensile stress, resulting in a remarkable change of the intensity of (0°, 35°, 0°) texture, while pyramidal ác+a? slip, forming (20°, 35°, 30°) texture, weakens with the increase of thickness strain in spite of stress state.
Key words: titanium alloy; texture; twinning; microstructure; drawing; stress state; cold rolling; drawing-bulging