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

Abstract

First-principles calculations were used to estimate the anisotropic elastic and thermal properties of Ti2lnX (X = C, N) and Zr2lnX (X = C, N) M2AX phases. The crystals’ elastic properties were computed using the Voigt-Reuss-Hill approximation. Firstly, the material’s elastic anisotropy was explored, and its mechanical stability was assessed. According to the findings, Ti2lnC, Ti2lnN, Zr2lnC, and Zr2lnN are all brittle materials. Secondly, the elasticity of Ti2lnX (X = C, N) and Zr2lnX (X = C, N) M2AX phase are anisotropic, and the elasticity of Ti2lnX (X = C, N) and Zr2lnX (X = C, N) systems are different; the order of anisotropy is Ti2lnN > Ti2lnC, Zr2lnN > Zr2lnC. Finally, the elastic constants and moduli were used to determine the Debye temperature and sound velocity. Ti2lnC has the maximum Debye temperature and sound velocity, and Zr2lnN had the lowest Debye temperature and sound velocity. At the same time, Ti2lnC had the highest thermal conductivity.

Calculation of Mechanical Properties, Electronic Properties, and Thermodynamic Properties of AuAl Crystal: First‐Principles Calculation

“…θ D can be used to characterize the strength of covalent bonds in solids: the greater the θ D , the stronger the covalent bond, and the strength of the covalent bond can indirectly reflect the hardness of the compound. [ 47 ] The θ D of 0 GPa AuAl is 246.69 and 332.87 K at 20 GPa, indicating the enhanced covalent bond strength, which corresponds to the previous analysis.…”

Realization of diversity in physical properties of Zr2Se(B1‐xSex) MAX phases through DFT approach

“…Generally, the elastic constants represent some important physical meaning of the material, for example, C 11 and C 33 indicate the ability to resist linear compression of the a– and c–axis in the directions [1000] and [0001], respectively 43 . For all compositions, C 33 > C 11 , implying that they are more incompressible along the c‐axis than along the a‐axis 44 . This is due to the chemical bonds and atomic arrangement.…”

First‐principles investigation of structural, mechanical, and optoelectronic properties of Hf2AX (A═Al, Si and X═C, N) MAX phases

“…The calculated value of “υ” for Hf 2 AX (A═Al, Si and X═C, N) MAX phases is less than its threshold, which indicates the brittle character of Hf 2 AX MAX phases. For hexagonal Hf 2 AX compounds, the expressions $${C}_{12} - \ {C}_{66}$$ and $${C}_{13} - \ {C}_{44}$$ refer to the Cauchy pressure ($${C}_P$$), 49–52 which is used to predict the brittleness or ductility of the studied compounds. If $${C}_{12} - \ {C}_{66} > 0$$ and $${C}_{13} - \ {C}_{44} > 0$$, the solid is ductile; otherwise, it is brittle.…”

“…48 The calculated value of "𝜐" for Hf 2 AX (A═Al, Si and X═C, N) MAX phases is less than its threshold, which indicates the brittle character of Hf 2 AX MAX phases. For hexagonal Hf 2 AX compounds, the expressions 𝐶 12 − 𝐶 66 and 𝐶 13 − 𝐶 44 refer to the Cauchy pressure (𝐶 𝑃 ), [49][50][51][52]…”