A first-principles study the effects of nitrogen on the lattice distortion, mechanical, and electronic properties of (ZrHfNbTa)C1-xNx high entropy carbonitrides.

Recently, high-entropy carbonitrides (HECNs) have attracted extensive attentions due to their outstanding comprehensive properties. However, the underlying physical mechanisms responsible for their excellent properties are not well understood. In this work, the effects of nitrogen (N) on the material properties of the newly-developed (ZrHfNbTa)C 1- x N x (x = 0.0–0.5) HECNs are systematically studied by the first-principles calculations. The obtained results reveal that the calculated properties of the HECNs match well with experimental data. The mechanical properties of the HECNs are closely associated with their local lattice distortion. The lattice distortion is exacerbated with the increase of N. Increasing N content also leads to increase their mass density and ductility, but decrease their lattice parameter, Young's modulus, shear modulus, hardness, fracture toughness, acoustic velocity, Debye temperature, and thermal conductivity. The additive of N can promote the charge transfer between metal and non-metal elements, but decrease the strength of metal-carbon and metal-nitrogen bonds. • The effects of nitrogen on high-entropy carbonitrides (HECNs) are initially clarified. • Lattice distortion of HECNs is identified and evaluated by a new index. • Nitrogen plays a pivotal role in improving the comprehensive properties of HECNs. • The charge transfer and bonding mechanisms of HECNs are elucidated completely. [ABSTRACT FROM AUTHOR]