Theoretical Strength of Borides and Quasibinary Boride Eutectics at High Temperatures

Abstract

The theoretical strength of LaB₆ and МеB₂ borides and a eutectic LaB₆–TiB₂ system is calculated with quasiharmonic approximation for uniaxial deformation in the temperature range between 0 and 2750 K. It is established that the linear temperature dependence of strength, typical of LaB₆, does not hold in the range 1300–2200 K. It is shown that the theoretical strength increases with higher temperatures. The same dependence is typical of the LaB₆–MeB₂ systems (Me is Ti, Zr, Hf) at 0.7 mol.% LaB₆.