X-ray parameters of a nanocrystalline titanium microstructure, obtained via cryodeformation

A study of how reducing thickness by rolling at liquid nitrogen temperatures affects the deformation parameters of BT1-0 titanium microstructure, conducted using x-ray diffraction (XRD). The nanograin structure that formed due to cryodeformation was studied by analyzing the relative integrated intensity of the diffraction peaks, and by determining the size of the crystallites (coherent scattering regions) L, and microstrain values ⟨ ε 2 ⟩ 1 / 2 . The obtained data were compared with the results of optical and transmission electron microscopy. The effect of slip and twinning activity on the parameters of the low-temperature deformation microstructure is analyzed. In ultrafine-grain and nanocrystalline titanium there is a close correlation between the size of the crystallites obtained using XRD, and the sizes of the grains observed during electron microscopic studies. It is established that there is a limiting average grain size that is attained by crystallites during the formation of a nanocrystalline state. The correlation between the grain sizes and the crystallites, typical for nanocrystalline materials, can indicate that the internal structure of the nanosized grains in nanocrystalline titanium obtained via cryomechanical grain structure fragmentation, is sufficiently perfect. The given results serve as a confirmation of the assumption that it is impossible for the dislocations responsible for lattice distortions to accumulate in nanograins.