Abstract It is a longstanding notion that alloying different sized elements can cause lattice distortion and phase transition in chemically complex alloys. However, a quantitative understanding of it remains difficult for traditional alloys, and becomes even more challenging for equimolar multicomponent alloys, also known as “high entropy alloys”, which recently emerged as a promising structural/functional material and have been attracting tremendous research interest due to their unique properties. In this work, we carried out extensive first-principles calculations on a series of equimolar complex alloys with a chemically disordered crystalline structure, and characterized their atomic-scale lattice distortions in terms of the local residual strains. Albeit the confounding chemical/geometric complexities, we are able to show that the average attributes of such an atomic-scale distorted lattice, such as the lattice constant and the overall magnitude of the distortion induced residual strains, can be predicted very well by a simple physical model taking into account the efficient packing of different sized atoms interacting in an effective elastic medium. The findings of our current research unveils the details of locally distorted atomic packing in chemically disordered complex alloys, which sheds quantitative insights into the unusual strengthening mechanism as recently discovered in high entropy alloys.

中文翻译：

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化学无序等摩尔复合合金中的原子级扭曲晶格

摘要 将不同尺寸的元素合金化会导致化学复杂合金的晶格畸变和相变是一个长期存在的观点。然而，对传统合金的定量理解仍然很困难，对于等摩尔多组分合金（也称为“高熵合金”）变得更具挑战性，它最近作为一种有前途的结构/功能材料出现并引起了巨大的研究兴趣。到他们独特的属性。在这项工作中，我们对一系列具有化学无序晶体结构的等摩尔复合合金进行了广泛的第一性原理计算，并根据局部残余应变表征了它们的原子级晶格畸变。尽管化学/几何复杂性令人困惑，我们能够证明，这种原子尺度扭曲晶格的平均属性，例如晶格常数和扭曲引起的残余应变的总体大小，可以通过一个简单的物理模型很好地预测，同时考虑到有效堆积不同大小的原子在有效弹性介质中相互作用。我们目前的研究结果揭示了化学无序复杂合金中局部扭曲原子堆积的细节，这为最近在高熵合金中发现的不寻常的强化机制提供了定量见解。考虑到在有效弹性介质中相互作用的不同尺寸原子的有效堆积，可以通过简单的物理模型很好地预测。我们目前的研究结果揭示了化学无序复杂合金中局部扭曲原子堆积的细节，这为最近在高熵合金中发现的不寻常的强化机制提供了定量见解。考虑到在有效弹性介质中相互作用的不同尺寸原子的有效堆积，可以通过简单的物理模型很好地预测。我们目前的研究结果揭示了化学无序复杂合金中局部扭曲原子堆积的细节，这为最近在高熵合金中发现的不寻常的强化机制提供了定量见解。