Due to the presence of multiple elements consisting of a range of atomic radii, local lattice distortion (LLD) is commonly observed in concentrated (and high entropy) alloys. However, since these elements also have diverse electronegativities, recent works show that atoms can have a range of atomic charges. In this work, using density functional theory (DFT), we investigate electronic charge distribution in face centered cubic (FCC) Ni-based alloys and find significant charge-density distortion in HEAs. Specifically, Cr atoms have large charge density distortion that results in a wide range of bond lengths, atomic charges, and electronic density of states in Cr-containing alloys. The charge distortion impacts the stacking fault energies (SFEs) as a wide range of SFEs are observed in Cr-containing alloys (e.g., NiCr, NiFeCr and NiCoCr), which are otherwise narrow and converged in non-Cr containing alloys such as NiFe, NiCo and NiFeCo. These observations provide insights into the role of local charge distortion towards local lattice distortion in HEAs and illustrate the effect of charge distortion on the mechanical properties of the alloys.

中文翻译：

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镍基浓缩合金中铬引起的局部电荷畸变


由于存在由一系列原子半径组成的多种元素，因此在浓缩（和高熵）合金中通常会观察到局部晶格畸变（LLD）。然而，由于这些元素也具有不同的电负性，最近的研究表明原子可以具有一系列原子电荷。在这项工作中，我们利用密度泛函理论 (DFT) 研究了面心立方 (FCC) 镍基合金中的电子电荷分布，并发现 HEA 中存在显着的电荷密度畸变。具体而言，Cr 原子具有较大的电荷密度畸变，导致含 Cr 合金中的键长、原子电荷和电子态密度范围较宽。电荷畸变会影响堆垛层错能 (SFE)，因为在含铬合金（例如 NiCr、NiFeCr 和 NiCoCr）中观察到各种堆垛层错能 (SFE)，而在不含铬的合金（例如 NiFe、NiFe、镍钴和镍铁钴。这些观察结果深入了解了 HEA 中局部电荷畸变对局部晶格畸变的作用，并说明了电荷畸变对合金机械性能的影响。