Preface: High-entropy alloy nanostructures: from theory to application

Abstract

Few areas of materials science have evolved as rapidly and dynamically as high-entropy alloys (HEAs). What began just two decades ago as a bold idea – first articulated by Brian Cantor and Jien-Wei Yeh – that chemical complexity itself could stabilise materials, has grown into a thriving research field spanning structural, functional, and catalytic applications. The Faraday Discussions ‘High-entropy alloy nanostructures: from theory to application’, held at the Royal Society of Chemistry in London, brought together researchers from across the world to examine a fundamental question at the heart of this concept: with multicomponent alloys now within reach, do they truly deliver beyond simpler systems, or does complexity risk obscuring purpose?

Over three days of lively debate, participants explored how disorder and elemental diversity influence stability, reactivity, and performance across different classes of high-entropy materials. Discussions ranged from advanced synthesis routes for homogeneous alloys and operando characterisation techniques to computational and theoretical approaches capable of capturing the effects of disorder and configurational entropy at the atomic level. Moreover, cutting-edge applications in the fields of electrocatalysis and magnet fabrication have been presented both in the oral as well as in the vivid poster sessions. True to the Faraday tradition, the most stimulating moments arose not only from the presentations themselves but also from the spirited discussions that followed – challenging assumptions, connecting disciplines, and inspiring new ideas for the future.

HEAs embody both opportunity and challenge. Their vast compositional freedom offers pathways to tailor material properties in unprecedented ways, while their structural and chemical complexity pushes the limits of synthesis, theory, and characterisation alike. As Dierk Raabe reminded the community, materials design must ultimately be guided by purpose – by the function we seek to achieve. In a field defined by nearly boundless compositional space, this is an essential perspective: more complexity does not necessarily mean better materials. Determining whether function truly scales with complexity requires close collaboration between experimental and computational researchers – a hallmark of this Faraday Discussions and a defining strength of this community.

The idea for this meeting traces back to another Faraday Discussions on nanoalloys in 2022, where several of the current organisers first met. That event focused mainly on simpler binary systems, but the term “HEA” surfaced repeatedly, hinting at a broader horizon. Informal conversations after the sessions – and perhaps a few pints shared in good company – planted the seed for a dedicated discussion on HEAs. In the spirit of entropy, that idea spread, evolved, and eventually crystallised into this milestone meeting.

We are deeply grateful to all authors, speakers, and participants for the enthusiasm, openness, and insight they brought to this meeting. The wide range of contributions – from synthesis and modelling to theory and application – demonstrates both the remarkable progress achieved in recent years and the many opportunities that still lie ahead. We would also like to extend our sincere thanks to everyone who helped make this meeting possible. The scientific committee – Nicola Morley, Robert Weatherup, and Damien Alloyeau – played an essential role in shaping a diverse and stimulating programme. Our session assistants, Syrine Krouna and Jack Swallow, ensured the discussions ran smoothly and energetically, making sure every voice was heard.

Throughout the planning, the event itself, and the preparation of this issue, we were expertly supported by the Faraday Discussions team at the Royal Society of Chemistry – Katie Ackermann, Irene Sanchez, Amy Lucas, Neith Charlesworth, and Stuart Govan. Their professionalism, good humour, and meticulous organisation made everything appear effortless. We also wish to thank the Royal Society of Chemistry staff at Burlington House for their warm hospitality and seamless coordination, which created the perfect setting for open and engaging discussion.

Last but not least, a part of the committee wants to thank Freddy Mercury (Queen) for stimulating a nano-alloy rocket science discussion, while keeping the melody of We Will Rock You in mind:

“Buddy, you're a scientist, mixing elements on a wish//You got five or more, all in one core//Big atoms, small atoms, they all explore//You make a structure that's strong and new//We will, we will nano-rock you!//–//Buddy, you're a modeler, computing with such pride//You simulate disorder, but solid solution stays inside//Entropy, cocktail effect – lattice distortions in view//You predict phases, how they behave too//We will, we will nano-rock you!//–//Buddy, you're the experimentalist, pulsing lasers with your might//You ablate, fragment, control the size just right//CrMnFeCoNi, or with Cu to explore//You reveal amorphous, crystalline core//We will, we will nano-rock you!//–//Everybody here, in chemistry's shining hall//We discuss catalysis, stability, diffusion and all//At nanoscale, high entropy makes us proud//Let's shout it out loudly, strong and loud://We will, we will nano-rock you!”

It is our hope that the papers and discussions collected in this volume will continue to inspire curiosity, encourage collaboration, and advance our shared understanding of how to harness complexity with purpose—turning entropy itself into a design principle for the materials of the materials of the future.

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