Thermal stability of nanocrystalline and ultrafine-grained titanium created by cryomechanical fragmentation

Using X-ray diffraction analysis methods, the authors have studied the effect of stepwise isothermal annealing in the temperature range 150–670 C on the deformation microstructure parameters of cryodeformed VT1-0 titanium with micron, submicron, and nanoscale grain sizes. The structural states were obtained by rolling at liquid nitrogen temperature. This study discusses the influence of dislocations and twins as elements of deformation microstructure on the thermal stability of crystallite sizes (coherent scattering regions) and the magnitude of microdeformations. The dependences of microhardness on annealing temperature have been determined for samples in different initial structural states.