AI 中文总结
该研究探讨多组分合金中调幅分解为何通常为单模态，并揭示特定相互作用排列可实现双模态失稳，为通过调幅分解工程化微观结构提供理论框架。
AI 中文摘要
在二元合金中，调幅分解只有一个自由能可以下降的组分方向。多组分合金具有更多可用的方向，但其元素通常以单一、伪二元模式一起分离。为什么会发生这种情况，以及什么条件会使两个独立方向变得不稳定？我们使用二元相互作用参数和规则溶液自由能的组分约束曲率来研究这些问题。在等摩尔BCC四元合金中，在500 K下，一个不稳定模态是最常见的结果，而15.2%的合金至少有两个不稳定模态。不同元素混合的倾向有助于解释对单一模态的偏好。然后我们展示了特定的相互作用排列，包括平衡的排斥三角形和吸引-排斥对，如何保证两个下坡方向。当这些方向具有相似的强度时，简化的相场模型产生广泛的不同局部固溶体纹理，而不是两个化学块。一个相特定的筛选确定了五种具有几乎平衡模态的临时合金，其中Cu-In-Ir-Ti提供了这种可能性的一个例子。因此，我们建立了一个基于基本二元相互作用倾向通过调幅分解工程化微观结构的理论框架。
英文摘要
In a binary alloy, spinodal decomposition has one composition direction in which the free energy can fall. A multicomponent alloy has more directions available, yet its elements usually separate together in a single, pseudobinary mode. Why does this happen, and what would allow two independent directions to become unstable? We examine these questions using binary interaction parameters and the composition-constrained curvature of the regular-solution free energy. Across equimolar BCC quaternaries, one unstable mode is the most common outcome at 500 K, while 15.2% have at least two. The tendency of unlike elements to mix helps explain the preference for one mode. We then show how particular arrangements of interactions, including a balanced repulsive triangle and an attractive-repulsive pair, guarantee two downhill directions. When those directions have similar strengths, simplified phase-field models produce a broad texture of locally different solid solutions rather than two chemical blocks. A phase-specific screen identifies five provisional alloys with nearly balanced modes, with Cu-In-Ir-Ti providing an example of this possibility. Thus, we establish a theoretical framework for engineering microstructures via spinodal decomposition derived from basic binary interaction tendencies.
Comments22 pages, 5 figures, 4 supplementary sections
