Cluster-Model-Based Composition Design Method for Fe-Cr-Ni-Based Medium- and High-Entropy Alloys

High-performance materials always possess specific chemical compositions, which strongly suggest the possible existence of some molecule-like structural units, in which the versatile but specific compositions are rooted. Our research group proposed the cluster-plus-glue-atom model in 2007, which is a short-range-order structural model that renders any structure with a structural unit consisting of a nearest-neighbor cluster plus a few outer-shell glue atoms. Here, the cluster-plus-glue-atom model is fully presented to show how to uncover the composition origin of high-entropy alloys. Examples are given in various industrial alloys with high-entropy feature, including stainless steels, superalloys, etc. Based on these composition analysis results, Fe-Cr-Ni-based medium- and high-entropy alloys with excellent mechanical properties are designed. The proposition of cluster-model-based molecule-like structural units supports a new perspective for the research of high-entropy alloys, facilitates the understanding of prevailing materials, and can be a useful tool to guide the exploration of new composition space.