Low energy mechanical treatment of non-stoichiometric titanium carbide powder

OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 23 No. 3 2021 after treatment. Figure 3 shows the X-ray diffraction patterns of the initial powder and that mechanically treated for different time. The diffraction peaks in all X-ray diffraction patterns correspond to the cubic TiC x lattice of the NaCl type. No peaks that belong to other phases or milling products from corundum grinding bodies were found in the X-ray diffraction patterns. The crystal lattice parameter of the powder in the initial state corresponds to the composition TiC 0.7 . An increase in the time of MT of TiC x powder does not lead to a change in the phase composition. However, a detailed analysis of the X-ray diffraction patterns showed that during MT of the powders their diffraction patterns change, the diffraction reflections are divided into two components. Fig. 3 . X-ray diffraction patterns of TiC x powder vs. mechanical treatment time Figure 4 shows fragments of the diffraction patterns of the (111) and (511) planes of the powder in the initial state and that after mechanical treatment. All diffraction profiles of the powder in the initial state are described by one function with high statisti - cal accuracy (Figure 4, a , b ). The diffraction profiles of the powders after MT are divided into two compo - nents (Figure 4, c , d ). This may indicate a different content of carbon (x) in TiC x powders [32-34, 38-40] ac- companied by occurrence of point defects, such as structural vacancies, or it can be related to ordering and disordering processes. The effect of structural defects on properties of the non-stoichiometric compounds is very significant [38]. In [38-40], it is assumed that a wide range of homogeneity from TiC 0.48 to TiC 1.00 is exhibited by exclusively disordered TiC х and, under specific conditions, ordered phases of M 2 C, M 3 C 2 , and M 6 C 5 type with cubic, triclinic, or rhombic lattices can form in it. In our case, the diffraction reflections cor - respond to the compositions TiC 0.65 and TiC 0.48 . An increase in the MT time for the TiC x powder from 5 to 100 hours does not lead to a change in the atomic ratio of carbon to titanium in both phases. Figure 5 shows the dependences of the CDD size ( a ) and crystal lattice microdistortions ( b ) on the MT time for structural components of the powders TiC 0.65 and TiC 0.48 . Figure 5, a shows that with an increase in the MT time to