Conditions of solid solution formation in (Ti, Zr, Hf)B2, (Zr, Hf, Nb)B2 and (Zr, Hf, Ta)B2 systems

The process of formation of solid solutions of the (Ti, Zr, Hf)B2, (Zr, Hf, Nb)B2 and (Zr, Hf, Ta)B2 composition was carried out. The heterophase microstructure is formed in this system, consisting of a solid solution and inclusions based on HfB2 and TaB2. It is shown that increasing the densification temperature it is possible to increase diffusion processes and, as a result, increase the elements solubility. The highest solubility was observed in the case of arc melting, when all components were in a liquid phase. However, for the (Zr, Hf, Ta)B2 composition, the TaB2 individual inclusions are formed. This is due to the fact that the energy of TaB2 formation significantly differs from the energy of other components.