Despite the advent of numerical modeling approaches and high-performance computing infrastructure, the design and development of corrosion-resistant high temperature alloys (> 500 °C) continue to be largely empirical and typically involve extensive experimentation. This is mainly due to the lack of a single unified physics-based model that can address the impact of multiple competing factors such as time, environment, alloy composition, microstructure, and geometry. The classical Wagner’s criteria have been foundational to estimate the minimum concentrations required of an oxide-forming element to establish and sustain a protective oxide scale. However, the formulation is primarily limited to lower-order alloy systems (binary alloys) and ignores the time dependence of subsurface compositional changes in the alloy. The lack of key data on the temperature and composition dependence of the solubility and transport of oxidants in multicomponent-multiphase alloys further exacerbates the problem. In the present work, a few of these limitations were addressed using a flux-based approach (FLAP) which tracks the spatiotemporal evolution of the fundamental flux balance between oxygen and the oxide-forming elements to enable the prediction of the formation of an external alumina scale in ternary NiCrAl alloys. The modeling results were validated with the literature findings and additional experimental work conducted in the present work.

尽管出现了数值建模方法和高性能计算基础设施，但耐腐蚀高温合金（> 500 °C）的设计和开发仍然主要依靠经验，并且通常涉及大量实验。这主要是由于缺乏一个统一的基于物理的模型来解决时间、环境、合金成分、微观结构和几何形状等多种竞争因素的影响。经典的瓦格纳标准是估计形成和维持保护性氧化皮所需的氧化物形成元素的最低浓度的基础。然而，该公式主要限于低阶合金系统（二元合金），并且忽略了合金中次表面成分变化的时间依赖性。缺乏关于多组分多相合金中氧化剂的溶解度和传输的温度和成分依赖性的关键数据进一步加剧了这个问题。在目前的工作中，使用基于通量的方法（FLAP）解决了其中一些限制，该方法跟踪氧和氧化物形成元素之间基本通量平衡的时空演变，从而能够预测外部氧化铝的形成三元 NiCrAl 合金中的尺度。建模结果通过文献发现和本工作中进行的额外实验工作进行了验证。