Evolution of microstructure and mechanical behavior of titanium during warm multiple deformation

The features of mechanical behavior and structure formation of commercial pure titanium during warm severe plastic deformation (WSPD) were studied. It is shown that after the strain e=6 at the temperature 400degreesC and the strain rate 10(-3) s(-1) a structure with a grain size of 0.2 mum. is formed. Its mechanical behavior at WSPD is described by a curve with a peak, stage of softening, and steady flow stage that is typical for dynamic recrystallization (DRX). New grains are formed inside of initial grains via formation of subgrains with the following increase in their misorientation according to the continuous mechanism of DRX. Localization of deformation in areas with sub-rain structure retards the formation of uniform microstructure. The microstructure uniformity of titanium can be increased by decreasing of initial grain size and applying of such deformation schemes which can provide uniform distribution of strain and stepwise decreasing of the processing temperature.