Innovative Design and Future Development of Chemically Complex Intermetallic Alloy

Intermetallic materials are bestowed by diverse ordered superlattice structures together with many unusual properties. In particular, the advent of chemically complex intermetallic alloys (CCIMAs), which are also called as the high-entropy intermetallic alloys (HEIMAs), has been received considerable attention in recent years and offers a new paradigm to develop novel metallic materials for advanced structural applications [1-5]. These newly emerged CCIMAs exhibit synergistic modulations of structural and chemical features, such as self-assembled long-range close-packed ordering, complex sublattice occupancy, and interfacial disordered nanoscale layer, potentially allowing for superb physical and mechanical properties that are unmatched in conventional metallic materials[1,2]. In this paper, we critically review the historical developments and recent advances in ordered intermetallic materials from the simple binary to chemically complex alloy systems. We are focused on the unique multicomponent superlattice microstructures, nanoscale grain-boundary segregation, and disordering, as well as the various extraordinary mechanical and functional properties of these newly developed CCIMAs. Finally, perspectives on the future research orientation, challenges, and opportunities of this new frontier are provided. This conceptual design of CCIMAs may lead to families of high-temperature structural materials that might avoid some of the drawbacks of high-temperature alloys currently in use, which will be of great interest for a broad range of aerospace, automotive, nuclear power, chemical engineering, and other applications.