标题： 基于DFPT的组分依赖性无序难熔二元合金的弹性张量衍生性质 显示英文标题

标题： Elastic tensor-derived properties of composition-dependent disordered refractory binary alloys using DFPT

摘要： 弹性张量为具有晶格应变的材料的力学行为提供了有价值的见解，例如无序二元合金。传统的应力-应变方法使得计算有序结构和单独定制的合金成分的弹性常数成为可能。然而，这种方法依赖于预先确定或迭代选择的应变张量。这对于对低对称性的无序材料进行系统、组成相关的研究构成了重大挑战。DFPT为应力-应变方法提供了一个有吸引力的替代方案：它允许无偏见地确定弹性张量，并且可以访问来自底层一般响应函数框架的局部场数据。尽管DFPT具有内在的灵活性和效率，但其在无序系统研究中的应用却有限。同时，为了改进复杂无序材料性质的预测建模，需要扩展量子力学数据。在这里，我们展示了使用DFPT计算的刚性离子和弛豫离子弹性张量的结果，针对一组全面的结构耐火体心立方(BCC)二元合金，包括Mo、Nb、Ta和W。我们通过计算力响应内部应变张量和位移响应内部应变张量，映射了每个无序结构晶格位点的弹性常数和剪切模量的量子驱动异质性以及相关弛豫场。所得到的属性——体积模量($B$)、剪切模量($G$)、杨氏模量($E$)、泊松比($\nu$)、普格比($B/G$)、柯西压力和弹性各向异性——作为所有耐火二元合金组成的函数进行了报告。在系统变化的Mo、Nb、Ta和W组成下，DFPT计算的耐火二元合金的机械性能数据与现有的实验数据高度一致。 显示英文摘要

摘要： The elastic tensor provides valuable insight into the mechanical behavior of a material with lattice strain, such as disordered binary alloys. Traditional stress-strain methods have made it possible to compute elastic constants for ordered structures and individually tailored alloy compositions. However, this approach depends on predetermined or iteratively-chosen strain tensors. This poses a significant challenge for systematic, composition-dependent studies of disordered materials with low symmetry. DFPT provides a compelling alternative to stress-strain methods: it allows for an unbiased determination of the elastic tensor, as well as access to local field data derived from the underlying general response function framework. Despite its intrinsic flexibility and efficiency, DFPT has seen limited application to the study of disordered systems. At the same time, there is a growing need for expanded quantum mechanical data to improve predictive modeling of complex disordered material properties. Here we present results for the rigid-ion and relaxed-ion elastic tensors computed using DFPT, for a comprehensive set of structural refractory BCC binary alloys of Mo, Nb, Ta, and W. We map the quantum-driven heterogeneity in elastic constants and shear modulus, and associated relaxation fields at each disordered structure lattice site, by computing the force response internal strain tensor and displacement response internal strain tensors. Derived properties -- the bulk modulus ($B$), shear modulus ($G$), Young's modulus ($E$), Poisson's ratio ($\nu$), Pugh's ratio ($B/G$), Cauchy pressure and elastic anisotropy -- are reported as a function of composition for all refractory binaries. The DFPT-computed mechanical properties data for the refractory binary alloys at systematically-varied Mo, Nb, Ta, and W compositions are in excellent agreement with available experimental data.