Relation between deformability and microstructures in a commercial pure Tisheet subjected to dual-temperature square-shaped deep drawing

Recent studies indicated that the deep drawing process at dual-temperatures could extend the drawability in many materials. This paper reports the stu dy of commercial pure Titanium (CP-Ti)(alpha -Ti) heated to the temperature range of 25-400 degreesC and deep-drawn by water-cooled square-shaped punc h. The CP-Ti exhibits almost triple drawability when the temperature is inc reased from room temperature to 400 degreesC. The location of the fracture point of CP-Ti sheets is on the corner of the cup wall near the die throat. The poor drawability at low temperature is due to the strain-hardening cau sed by reorientation bands (RBs). The active slip system at elevated temper ature promotes the drawability of CP-Ti. The X-ray diffraction studies show the tendency of slip system to be active on the prismatic plane at similar to 200 degreesC and on the pyramidal plane at similar to 400 degreesC. The process at 400 degreesC shows the microstructure with the micro-shear band s (MSBs) intersection induced by the heated die and the cooled punch. The M SB-MSB intersection prevents the further thinning of the cup wail and resul ts in the superior deep drawability by virtue of better ductility.