Mechanical Properties of TiC Nanowire from DFT Calculations

Abstract

Mechanical properties of TiC nanowire (TiCNW) have been investigated using the density functional theory, the full-potential augmented plane wave plus local orbital method (FLAPW + lo), by means of Wein2 k package. Infinite and free-standing nanowire in periodic positions was simulated by supercell approach, and the optimized structure and bond length were calculated. Young’s modulus of TiC nanowire and bulk TiC is obtained by the generalized gradient approximation and bulk modulus using the phonopy package. Additional modules are also obtained using these two modules. Gruneisen parameter γ and heat capacity at constant pressure CP at temperatures (0–1000 K) were calculated by the quasi-harmonic approximation. According to our results, the mechanical properties of bulk TiC are in good agreement with the available theoretical and experimental data. Young’s modulus of TiC nanowire is 4.09 times bigger than that of bulk TiC. Bulk modulus and shear modulus of TiCNW are 4.78 and 3.96 times bigger than those of bulk TiC, respectively. The increase in Young’s modulus, bulk modulus, and shear modulus is due to the bonding of Ti atoms to each other in relaxed structure. CP and γ of TiCNW increase with temperature; however, at a specific temperature, γ of TiCNW is more, and CP of TiCNW is less than those of bulk TiC.