Regularities of the influence of temperature and pressure on the grain size in the synthesized intermetallic compound Ni₃Al

The intermetallic compound Ni₃AI (γ′-phase, ordered solid solution) is the main strengthening phase of nickel superalloys is, the content of which in modern superalloys reaches up to 0.89. The efficiency of the intermetallic phase as a heat-resistant component in large part limited by low ductility and by strength in a wide temperature range accordingly. An increase in strength limit of the intermetallic component is possible with a decrease in grain size less than a critical value, less than 10 microns. Application of the known methods of plastic deformation for refining an intermetallic grain is almost impossible, but it is physically justified in the period of the grain structure nucleation under non-equilibrium conditions of the exothermic reaction of an intermetallic compound formation in a powder mixture of nickel and aluminum. The retention of low-dimensional grain structure in the synthesized intermetallic compound is possible with combining the processes of crystallization and compaction of the high-temperature synthesis product. This paper presents the results of investigation of the influence of high-temperature synthesis product deformation on the formation of a grain structure in a Ni₃Al intermetallic compound synthesized under pressure. (paper)