Yao Hu

What inspired you to pursue this research topic, and how has your understanding of it evolved throughout your PhD journey?

I have always been fascinated by one of the exciting aspects of materials science, that how subtle structural changes at the atomic level can have a profound impact on macroscopic material properties. And I was particularly drawn to the opportunity to use neutrons as a probe, which I found to be a very powerful and interesting tool for studying structure at atomic level. My research focuses on characterizing and understanding local lattice distortions in alloys, which is a very subtle structural feature but plays an important role in mechanical properties of the material I studied. At the beginning of my PhD, my understanding of the topic was quite simple. I viewed it as a single and well-defined effect. But as I delved deeper into it, I realized that the phenomenon is far more complex and can arise from multiple underlying mechanisms. More importantly, I learned that local lattice distortions are coupled with the intrinsic thermal vibrations of atoms, which requires careful experiments and analyses. This evolution in understanding has been one of the most fun parts of my PhD journey.

Can you describe a key finding or insight from your research that you’re especially proud of and why it matters in your field?

A key insight from my research is the experimental evidence of the temperature dependence of local lattice distortions. Previously, these distortions were widely assumed to be temperature independent, largely because of the experimental challenge in decoupling them from the thermal effect. This insight helps explain the temperature-insensitive elastic modulus observed in this family of materials, which is useful in many industrial applications. More broadly, it provides a new perspective on the role of local lattice distortions in mechanical properties, which is crucial given that these materials are considered promising candidates for high-temperature applications.

How do you hope your research will be used or built upon after your defense — whether in academia, industry, or society at large?

I hope the findings from my work can help explain temperature-dependent properties in these materials and be incorporated into the design of more reliable and more heat-resistant alloys for high-temperature applications, such as aerospace engines. I also hope the methodologies and insights from my research will inspire further studies of other structural features in this class of materials and contribute to the development of advanced materials in both academic and industrial contexts.

What role has SwedNess played in your journey?

SwedNess has played a vital role in my PhD journey by providing opportunities for specialized courses, extensive hands-on training and vibrant annual conferences. Through SwedNess, I had the opportunity to visit several world-leading neutron facilities, which significantly broadened my international perspective on neutron science. The extended stay at the ISIS Neutron and Muon Source and the University of Sheffield was an important part of my development, during which I have deepened my technical expertise while also built valuable connections and collaborations. I have also greatly valued the friendships I formed within the graduate school. These experiences have been invaluable not just for my professional development, but also for my personal growth.

Thesis: Local lattice distortions in refractory high-entropy alloys