Predictions of structural, electronic, mechanical, and thermodynamic properties of TMBCs (TM = Ti, Zr, and Hf) ceramics

Abstract

In the present work, we have investigated the structural, electronic, elastic, and thermodynamic properties of transition‐metal boron‐carbon compounds (TMBCs) (TM = Ti, Zr, Hf) using the first‐principles calculations. The results showed that TMBCs are energetically and thermodynamically stable, and the sequence of phase stability is HfBC > ZrBC > TiBC. B‐C bonds can be formed in TMBCs ceramics due to the strong hybridization between B‐2p and C‐2p states. The elastic anisotropies of TMBCs were illustrated by elastic anisotropy indexes, 3D surface constructions, and 2D projections, and the results indicated that the sequence of elastic anisotropy is ZrBC > TiBC > HfBC. Finally, the calculated minimum thermal conductivities, based on the Clarke's and Cahill's models, of all TMBCs are anisotropic with the sequence of ZrBC > TiBC > HfBC.

Simultaneous enhancement of hardness and wear and corrosion resistance of high‐entropy transition‐metal nitride

“…Meanwhile, the polycrystalline isotropies B and G calculated from the elastic constants increase with the addition of solute atoms, from 308 and 138 GPa for NbN to 328 and 158 GPa for NbMoN, and then to 334 and 172 GPa for (NbMoTaW)N. These results suggest enhanced bond strength and bond directionality, and it is generally accepted that high B and G are correlated with high hardness. Moreover, larger Young's modulus corresponds to a stiffer material 60 . As seen from data in Table 3, the order of Y is (NbMoTaW)N > NbMoN > NbN, which is the same order as the indentation elastic modulus shown in Figure 4B.…”

“…Moreover, larger Young's modulus corresponds to a stiffer material. 60 As seen from data in Table 3, the order of Y is (NbMoTaW)N > NbMoN > NbN, which is the same order as the indentation elastic modulus shown in Figure 4B. Consequently, the HEN possesses the higher hardness due to its higher elastic constants and elastic moduli caused by the incorporation of multi-element solid solution atoms.…”

Anisotropic Elastic and Thermal Properties of M2InX (M = Ti, Zr and X = C, N) Phases: A First-Principles Calculation

“…In this work, M 2 InX (M = Ti, Zr and X = C, N) MAX phases were analyzed using the Cambridge Sequential Total Energy Package (CASTEP) [15,16] of Density Functional Theory (DFT) [17]. The interactions between electrons and ionic nuclei were calculated using on-the-fly generation (OTFG), ultrasoft pseudopotentials (USPPs), and the Perdew-Wang generalized-gradient approximation (PW91) [18][19][20][21] method in generalized gradient approximation (GGA) was utilized to model exchange correlation potential.…”

Exploring the electronic, mechanical, anisotropic, and optical properties of ternary silicides TM2Si2Ys (TM = Cu, Ir, Os, Pt, Pd, Rh, Ru) from a first principles investigations

“…As a valid method to describe the elastic anisotropic behavior of a crystal completely, the three‐dimensional (3D) surface construction is depicted to further illustrate the elastic anisotropic features. Besides, for the different structural systems (including tetragonal, orthogonal, and hexagonal structures) correspond to the different anisotropy formulas: [ 41, 47, 48 ] …”

“…As a valid method to describe the elastic anisotropic behavior of a crystal completely, the three-dimensional (3D) surface construction is depicted to further illustrate the elastic anisotropic features. Besides, for the different structural systems (including tetragonal, orthogonal, and hexagonal structures) correspond to the different anisotropy formulas: [41,47,48] 1…”