Pressure‐induced incompressibility and point singularity of mechanical properties of TaC in NiAs‐type structure

The structural and elastic properties of TaC in NiAs‐type structure under high pressure have been investigated using first principles calculations based on density functional theory. Results indicate that the incompressibility along the c‐axis of TaC exceeds that of diamond under higher pressure. Particularly, an interesting point singularity exists in its mechanical properties as the pressure increases from 20 GPa to 40 GPa. The minimal shear modulus, Young's modulus, Debye temperature, and maximum Poisson ratio of TaC are simultaneously obtained at 28 GPa. The calculations of hardness indicate that the NiAs‐type TaC crystal possesses excellent mechanical properties. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)