In situ synchrotron research of phase formation in mechanically activated 3Ti+Al powder composition during high-temperature synthesis under the condition of heating with high-frequency electromagnetic fields

An in situ synchrotron study of the specific features of the phase formation dynamics in mechanically activated 16wt% Al+Ti powder composition is described, the high-temperature synthesis being carried out under the condition of high volume inflammation by means of inductive heating. The kinetics of the phase formation were registered with an experimental complex, especially designed, constructed and adjusted for the method of dynamic diffraction analysis in synchrotron radiation beams. It has been experimentally in situ shown that increasing the time of mechanical activation of the initial powder mixture reduces the temperature at which components start to react and the time of realization of the high-temperature synthesis. With the latter set at 1min of mechanical activation, the temperature of the reaction in the mixture is T = 603 degrees C; at 3min of mechanical activation, T = 442 degrees C; and at 7min, T = 359 degrees C. The maximum burning temperatures are: for 1min of mechanical activation, T-max = 1080 degrees C; for 3min, T-max = 1003 degrees C; and for 7min, T-max = 820 degrees C. It was found that formation of both stable compounds Ti3Al, TiAl3, TiAl2, TiAl and metastable phases Ti9Al23, Ti5Al11, Ti2Al5, Ti3Al5 occurs at the stage of primary structure formation, before the system goes to thermal explosion. High-temperature synthesis of a mixture of the studied composition takes place without formation of a liquid phase, in the solid-phase combustion mode. It was found that the increase in the time of mechanical activation of the initial powder mixture contributes to the formation of a product with a dominant content of intermetallic compound Ti3Al. By synthesis of the powder mixture of composition 16wt% Al+Ti, mechanically activated for 7min, the content of Ti3Al in the final product was found to be 68%.