  We report the mechanical properties of cubic boron nitride (c-BN) and diamond
under the combined impact of dynamical pressure and temperature, calculated
using ab initio molecular dynamics. Our study revealed a pronounced sensitivity
of the mechanical properties of c-BN to applied pressure. Notably, c-BN
undergoes a brittle-to-ductile transition at ~220 GPa, consistent across
various dynamical temperatures, while diamond exhibits no such transition.
Furthermore, the Vickers hardness profile for c-BN closely mirrors that of
diamond across a spectrum of temperature-pressure conditions, highlighting
c-BN's significant mechanical robustness. These results underscore the superior
resilience and adaptability of c-BN compared to diamond, suggesting its
potential as an ideal candidate for applications in extreme environments.
