Anisotropic elastic properties and ideal uniaxial compressive strength of TiB₂ from first principles calculations

【摘要】 The structural, anisotropic elastic properties and the ideal compressive and tensile strengths of titanium diboride（TiB₂） were investigated using first-principles calculations based on density functional theory. The stress–strain relationships of TiB₂ under 1010, 1210, and 0001 compressive loads were calculated. Our results showed that the ideal uniaxial compressive strengths are |σ ₁₂₁₀| = 142.96 GPa, |σ₀₀₀₁| = 188.75 GPa, and |σ₁₀₁₀| = 245.33 GPa, at strains -0.16,-0.32, and-0.24, respectively. The variational trend is just the opposite to that of the ideal tensile strength withσ 1010 = 44.13 GPa, σ₀₀₀₁= 47.03 GPa, and σ₁₂₁₀= 56.09 GPa, at strains 0.14, 0.28, and 0.22, respectively. Furthermore, it was found that TiB₂ is much stronger under compression than in tension. The ratios of the ideal compressive to tensile strengths are 5.56, 2.55, and 4.01 for crystallographic directions 1010, 1210, and 0001, respectively. The present results are in excellent agreement with the most recent experimental data and should be helpful to the understanding of the compressive property of TiB₂.更多还原

【Abstract】 The structural, anisotropic elastic properties and the ideal compressive and tensile strengths of titanium diboride（TiB₂） were investigated using first-principles calculations based on density functional theory. The stress–strain relationships of TiB₂ under 1010, 1210, and 0001 compressive loads were calculated. Our results showed that the ideal uniaxial compressive strengths are |σ ₁₂₁₀| = 142.96 GPa, |σ₀₀₀₁| = 188.75 GPa, and |σ₁₀₁₀| = 245.33 GPa, at strains -0.16,-0.32, and-0.24, respectively. The variational trend is just the opposite to that of the ideal tensile strength withσ 1010 = 44.13 GPa, σ₀₀₀₁= 47.03 GPa, and σ₁₂₁₀= 56.09 GPa, at strains 0.14, 0.28, and 0.22, respectively. Furthermore, it was found that TiB₂ is much stronger under compression than in tension. The ratios of the ideal compressive to tensile strengths are 5.56, 2.55, and 4.01 for crystallographic directions 1010, 1210, and 0001, respectively. The present results are in excellent agreement with the most recent experimental data and should be helpful to the understanding of the compressive property of TiB₂.更多还原