Abstract

A theoretical study was conducted to analyze electronic, elastic, and thermodynamic properties and the structural stability of the intermetallic materials Al₃Ti_1−xZr_x for tetragonal-D0₂₂ and cubic-L1₂ structures carried out based on DFT. The findings indicate that the D0₂₂ phase has demonstrated more stability than the L1₂ phase and the possibility of a structural phase transition under pressure effect for concentrations x = 0.25 and x = 0.5. With increasing x concentration, the resulting lattice parameters drop. The density of states at the Fermi level, determines the electronic stability exhibited by these compounds. A pseudo-gap in proximity to the Fermi level implies the establishment of directional covalent bonding. The electronic structures support the phase stability results and show that the bonding in these compounds is more directed. Measurement techniques are employed to determine the number of bonding electrons per atom and the coefficient of electronic-specific heat. Both the mechanical as well as elastic properties of the considered alloys are examined. The findings demonstrate that all explored alloys are brittle, and D0₂₂ phase is stiffer than the L1₂ phase. The thermal characteristics are predicted via the quasi-harmonic Debye model.

Graphical abstract

中文翻译：

---

Zr浓度对D022/L12-Al3Ti热力学、弹性、电子和结构稳定性影响的理论研究

摘要

基于密度泛函理论（DFT）进行了理论研究，分析了四方-D0 ₂₂和立方-L1 ₂结构的金属间材料Al ₃ Ti _1−x Zr _{x的电子、弹性和热力学性质以及结构稳定性。}研究结果表明，D0 _{22相比 L1 2}相表现出更高的稳定性，并且在浓度x  = 0.25 和x = 0.5的压力作用下可能发生结构相变 。随着x浓度的增加，所得晶格参数下降。费米能级的态密度决定了这些化合物所表现出的电子稳定性。接近费米能级的赝能隙意味着定向共价键的建立。电子结构支持相稳定性结果，并表明这些化合物中的键合更加定向。采用测量技术来确定每个原子的键合电子数量和电子比热系数。检查所考虑合金的机械性能和弹性性能。研究结果表明，所有探索的合金都是脆性的，并且D0 ₂₂相比L1 ₂相更硬。热特性通过准谐波德拜模型进行预测。

图形概要