Abstract: Multicomponent alloys have garnered significant interest due to their vast compositional flexibility, enabling precise tailoring of microstructures and properties for advanced technological applications. A comprehensive understanding and control of their microstructures fundamentally depends on quantitative, atomic-scale characterization. Atom probe tomography (APT), with its 3D imaging capability and near-atomic resolution, has emerged as a powerful technique for microstructural analysis. This review systematically summarizes recent advances in the application of APT for characterizing microstructural features across multiple length scales, including atomic clusters (0D), dislocation segregation (1D), interfaces and planar defects (2D), and precipitates (3D). We highlight how APT reveals the nanostructural complexity arising from multi-element interactions and provides critical atomic-scale insights that inform the design and optimization of high-performance multicomponent alloys. Finally, we discuss current challenges and outline future research directions for the continued development and application of APT in this field.

Key words: Atom probe tomography, Multicomponent alloy, Microstructure, Atomic-scale characterization, Mechanical property