Structural transformations in single-crystalline titanium under high-pressure cold and cryogenic deformation

Abstract

The structure of an iodide titanium pseudo-single crystal subjected to severe plastic deformation in Bridgman anvils under a pressure of 8 GPa at room (293 K) and cryogenic (80 K) temperatures has been examined using methods of X-ray diffraction analysis and electron microscopy. It has been shown that, in the course of deformation, the original α titanium pseudo-single crystal undergoes the α→ ω transition. A decrease in the temperature of deformation to 80 K leads to the activation of twinning. At degrees of deformation lower than e = 6 titanium deformed at 293 K experiences more substantial strain hardening. In the course of subsequent deformation at 293 K, when e > 6, dynamic recrystallization begins, which is accompanied by the softening of the titanium. A decrease in the temperature of deformation to 80 K suppresses the recrystallization; therefore, the titanium deformed in liquid nitrogen shows a higher increase in the microhardness at degrees of deformation 6 < e < 10.