Chemical short-range order in complex concentrated alloys (CCAs): a review

Complex concentrated alloys (CCAs) have emerged as a versatile class of metallic materials exhibiting promising and, in some cases, exceptional mechanical properties. Increasing attention has been directed toward the role of chemical short-range order (CSRO) as a contributing factor to these behaviors, motivating its consideration as a potential design parameter for tailoring alloy performance. A growing body of work has explored this relationship, with atomistic simulations providing detailed insights into the emergence of non-random chemical configurations in multicomponent systems. Concurrently, experimental efforts have advanced significantly, yielding increasingly refined observations of CSRO, albeit with variations in interpretation depending on the technique and resolution. In this perspective review, the current understanding of CSRO is synthesized by examining both computational predictions and experimental observations. Emphasis is placed on evaluating available characterization and modeling approaches and on clarifying how CSRO manifests across length scales and influences mechanical response. By integrating these complementary perspectives, this work provides a structured assessment of the present capabilities for identifying, quantifying, and leveraging CSRO in CCAs, while outlining pathways for continued refinement in this evolving field.