Data-Driven Modeling of Composition-Processing-Microstructure Relations for Recycled Aluminum Cast Alloys

Aluminum is the second most widely used metal worldwide, with essential roles in transportation, construction, packaging, and energy infrastructure. Recycling aluminum can save up to 95% of the energy required for primary production, making it a cornerstone of low-carbon manufacturing. However, recycled aluminum alloys inevitably contain higher levels of iron, which promotes the formation of brittle microscopic phases that degrade performance and limit industrial use. These phases can appear in different forms and dispersion depending on alloy composition and processing. Yet, practical guidelines for controlling them remain largely empirical and qualitative, especially when data are limited. To improve this situation, this work separates two key questions that are often conflated in alloy design: which phase type forms, and how strongly that phase affects material behavior once it appears. Using data representative of industrial conditions, we show how alloy chemistry and processing history determine which phases form and govern whether these phases develop as a few large, platelet-like features or as many small, compact particles. By clarifying these distinct roles of composition and processing, the results provide a simple and actionable framework for mitigating deleterious iron-rich phases in recycled aluminum alloys and enabling more quantitative, predictable, and impurity-tolerant sustainable alloy design.