Defects in boron carbide: First-principles calculations and CALPHAD modeling

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• 作者：Arkapol Saengdeejing ; ^{aksaengdeejing@gmail.com} ; James E. Saal ; Venkateswara Rao Manga ; Zi-Kui Liu
• 关键词：CALPHAD ; First-principles calculations ; Debye&ndash ; Grü ; neisen model ; Boron carbide ; ¦Â-Boron
• 刊名：Acta Materialia
• 出版年：2012
• 出版时间：December, 2012
• 年：2012
• 卷：60
• 期：20
• 页码：7207-7215
• 全文大小：519 K

文摘

The energetics of defects in B_4+xC boron carbide and ¦Â-boron are studied through first-principles calculations, the supercell phonon approach and the Debye-Gr¨¹neisen model. It is found that suitable sublattice models for ¦Â-boron and B_4+xC are B₁₀₁(B,C)₄ and B₁₁(B,C) (B,C,Va) (B,Va) (B,C,Va), respectively. The thermodynamic properties of B_4+xC, ¦Â-boron, liquid and graphite are modeled using the CALPHAD approach based on the thermochemical data from first-principles calculations and experimental phase equilibrium data in the literature. The concentrations of various defects are then predicted as a function of carbon composition and temperature.