EFFECT OF PRELIMINARY ACTIVATION OF TiAL POWDER ON THE PROCESS OF MECHANOCHEMICAL SYNTHESIS OF (FE, Ti)3AL INTERMETALLICS.

The effect of mechanical activation of tial powder on the structural and phase transformations in mechanochemical synthesis of the powder mixture of the composition 60.8fe + 39.2-i-1, intended to produce fe3al intermetallics, alloyed with titanium was studied. using a semi-empirical miedema's model, the changes of Gibbs energy for the binary ti-al, fe-ti and fe-al systems were calculated. the results showed that the driving force for the formation of intermetallic phases for all the binary systems is higher as compared to the formation of solid solutions and amorphous phases. a range of compositions was established, at which the formation of amorphous phases in the binary Ti-al and fe-al systems is possible. carrying out the mechanical activation of tial intermetallic powder in a high-energy planetary mill allowed reducing the size of a coherent scattering region from 280 to 9 nm with a partial amorphization. the formation of particles with a homogeneous microstructure consisting of intermetallic phase (Fe, Ti)₃al and laves phases -- Fe₂ti was revealed in the process of mechanochemical synthesis of a powder mixture 60.8fe + 39.2 Tial when using nanostructural tial powder. the change in the region of coherent scattering of powders of 60.8fe + 39.2Tial mixture, produced by the method of mechanochemical synthesis, was evaluated and it was established that interaction of a nanostructural powder tial with fe begins to occur when the size of a coherent scattering region becomes <70 nm. the resulting product has an amorphous-nanocrystalline structure with a size of the coherent scattering region of <15 nm. the use of the developed powder in thermal spraying technologies will allow producing coatings based on Fe₃al intermetallics with a nanocrystalline structure, a higher modulus of elasticity and ductility. [ABSTRACT FROM AUTHOR]