First-principles study of the thermodynamic and elastic properties of eutectic Fe

DOI：

10.1016/j.actamat.2011.11.046

发表时间：

2012-02

期刊：

Acta Materialia

影响因子：

9.4

通讯作者：

中科院分区：

材料科学1区

文献类型：

作者：

Li-Fang Zhu;M. Friák;A. Dick;B. Grabowski;T. Hickel;F. Liot;D. Holec;A. Schlieter;U. Kühn;J. Eckert;Z. Ebrahimi;H. Emmerich;J. Neugebauer

使用量子力学计算研究了涵盖广泛 Ti 浓度的 Ti-Fe 合金。采用密度泛函理论，我们正确地再现了实验 Fe-Ti 相图的选定关键特征。详细分析稳定相的电子结构，根据费米能 (DOS(EF)) 下的组成和态密度之间的强相关性，为热力学稳定性提供了解释。基于这一见解，我们通过计算均质弹性常数的成分依赖性，扩展了对各种 Fe-Ti 合金的单晶和多晶弹性的研究。这些量及其成分依赖性为 β-Ti(Fe) 相的延展性和柔软性的起源提供了直接解释。具体来说，我们发现该相的 Fe 浓度接近与机械不稳定开始相关的阈值。通过将热力学稳定性和机械稳定性联系起来，我们用机械稳定性降低来解释 β-Ti(Fe) 的柔软性和延展性，而机械稳定性降低与 β-Ti(Fe) 中 DOS(EF) 的增加有关。

Ti–Fe alloys covering a broad range of Ti concentrations are studied using quantum-mechanical calculations. Employing density functional theory, we correctly reproduce selected key features of the experimental Fe–Ti phase diagram. Analyzing the electronic structure of the stable phases in detail provides an explanation for the thermodynamic stability in terms of the strong correlation between the composition and density of states at the Fermi energy (DOS(EF)). Based on this insight, we extend our study on both single-crystalline and polycrystalline elasticity of various Fe–Ti alloys by computing the compositional dependence of homogenized elastic constants. These quantities and their compositional dependence provide a direct explanation for the origin of the ductility and softness of the β-Ti(Fe) phase. Specifically, we find that this phase has an Fe concentration close to a threshold value connected with the onset of mechanical instability. By interlinking thermodynamic and mechanical stabilities we explain the softness and ductility of the β-Ti(Fe) in terms of a reduced mechanical stability that is connected with an increased DOS(EF) in the β-Ti(Fe).

First-principles study of the thermodynamic and elastic properties of eutectic Fe–Ti alloy

文献摘要

被引文献

相似文献