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

Using the methods of x-ray diffraction analysis, the influence of stepwise isothermal annealing in the temperature range 150–670 °C on the parameters of the deformation microstructure of cryodeformed titanium VT1-0 with micron, submicron and nanoscale grain sizes were studied. The studied structural states were creation by rolling at the temperature of liquid nitrogen. The influence of dislocations and twins as elements of a deformation microstructure on the thermal stability of crystallite sizes (regions of coherent scattering) and the magnitude of microdeformations is discussed. The dependences of the microhardness on the annealing temperature are found for samples with different initial structural states. (author)