Mechanical deformation modes and anisotropy of IVB transition metal nitrides

This paper studies the deformation modes and anisotropy of the IVB transition metal nitrides TiN, ZrN, and HfN using the plane-wave density functional theory. The values of elastic modulus and hardness of the TiN, ZrN, and HfN are calculated and analyzed in detail. This result suggests typical elastic anisotropy, which increases in the order of TiN → ZrN → HfN. This phenomenon results in inevitable lattice distortion and microcracks. The minimum value of thermal conductivity of the polycrystalline system decreases in the order of TiN → ZrN → HfN. The thermal conductivity of single crystals in each crystal orientation presents a nearly anisotropic thermodynamic property.