发表机构
University of Manitoba（曼尼托巴大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
研究发现高熵合金中价电子浓度判据已隐含原子尺寸效应，其成功与失效均由尺寸-电子数协方差决定。
AI 中文摘要
价电子浓度（VEC）是高熵合金（HEAs）中预测FCC相对于BCC稳定性的最广泛使用的指标，但它是一个成分平均值，不携带关于原子尺寸的信息。利用宏观原子模型，我们表明混合焓几乎对尺寸不敏感，即使组成元素的体积相差2倍，其变化也小于6%，因此尺寸只能作用于电子数。该作用恰好等于原子表面$V^{2/3}$与价电子数的协方差除以其平均值。这个协方差不是自由的。在用于构建高熵合金的元素中，体积和价电子数强烈负相关，因此在265种已表征的合金中，尺寸校正后的电子数只是VEC的仿射重缩放，并未改善任何预测。VEC已经隐含了原子尺寸，这解释了其成功之处，并定位了其在大的富电子元素中的失效。化学通过一个开关元素设定焓。
英文摘要
The valence electron concentration (VEC) is the most widely used predictor of FCC against BCC stability in high-entropy alloys (HEAs), yet it is a compositional average carrying no information about atomic size. Using the macroscopic atom model, we show that the mixing enthalpy is almost size-blind, shifting by less than 6\% even when constituent volumes differ by a factor of 2, so that size can act only on the electron count. That action equals exactly the covariance of the atomic surface $V^{2/3}$ with the valence electron count, divided by its mean. This covariance is not free. Volume and valence are strongly anti-correlated across the elements used to build HEAs, so the size-corrected count is an affine rescaling of VEC over 265 characterized alloys and improves no prediction. VEC already encodes atomic size, which explains its success and locates its failure among large, electron-rich elements. Chemistry sets the enthalpy through one switch element.
