Application of the Method of Dynamic Diffractometry Using Synchrotron Radiation to Study Phase Formation Processes during the Synthesis of a Mechanically Activated Ti–Al–C Mixture

Abstract

Using the method of dynamic diffractometry with the use of synchrotron radiation beams, experimental studies of phase formation processes occurring during the high-temperature synthesis of mechanically activated powder mixture Ti + Al + C were conducted. High-temperature synthesis has been carried out in situ in thermal explosion mode using a microwave induction heater on an experimental complex adapted to the method of dynamic diffractometry. The experiments were conducted at the “Diffraction Cinema” station of VEPP-3, channel 5B, at the Budker Institute of Nuclear Physics, Siberian Branch, Russian Academy of Sciences. It has been experimentally shown that the synthesis of a composite material occurs in multiple stages. The onset of phase changes begins at a temperature of approximately 870°C. Initially, the formation of intermetallic compound TiAl₃ is observed. Then a Ti–Al melt is formed with the release of TiC grains, which provides the main heat release and initiates a thermal explosion reaction. Further, the Ti–Al melt due to the dissolution of TiC grains in it is saturated with carbon, and when the temperature reaches 1800°C, MAX phase Ti₂AlC crystallizes from it. The maximum amount of this phase is fixed at the exposure stage. With a decrease in temperature, along with Ti₂AlC, MAX phase Ti₃AlC₂ is formed. At this stage, by controlling the temperature, it is possible to control the content of MAX phases in the reaction product. The composition of the final product includes Ti₃AlC₂, Ti₂AlC, and TiC.