Kinetics of Interaction of ПT-4 Grade Ti with VN and Graphite during Mechanical Alloying

A detailed x-ray diffraction study of test samples selected after each hour of the mechanochemical processing of two equimolar (T-4 Ti)-VN and (T-4 Ti)-VN-C blends in a high-energy planetary ball mill is carried out.Initial mixtures contain individual VN and Gr (graphite), as well as TiH2 and -Ti phases in T-4 grade titanium powder.Because of the crystal-structure refinement of each phase existing in the mixtures milled, it is shown that the interaction between the charge components occurs in two stages during 10 hours of processing.Namely, the formation of vacancies in VN phase dominates at the first stage, which is accompanied by embedding of released V atoms into the tetrahedral voids of the TiH2 structure and dehydrogenating of TiH2.The second stage is characterized by embedding of Ti atoms forming because of -Ti destruction into VN crystal lattice with a concurrent embedding of carbon atoms into the TiH2 structure.The final products of the mechanochemical synthesis, in addition to -Ti, contain the following compounds: TiV0.33H0.66((T-4 Ti)-VN blend) and TiV0.33H0.660.22 ((T-4 Ti)-VN-C blend) on the base of TiH2 hydride, as well as V0.67Ti0.33N0.93 (both blends) solid solution on the base of VN.Nanoscale final products (crystallite size of up to 20 nm) of the mechanical alloying will be compacted to determine the stability of the new phases formed and to study the properties of compacts prepared in order to find out prospects of their further application.