Yao Hu

My name is Yao Hu and I was born in Yunnan, China in 1997. I received my bachelor’s degree in Materials Physics from Jilin University, and master’s degree in Materials Physics and Chemistry from Shanghai University in June 2021. During my master thesis I studied the thermoelectric transport properties of BiAgSeS, a phase-transition material, which arouse my interest in phase transformations especially from an even more microscopic point of view.

My project in SwedNess will be focused on the study of microstructures within high entropy alloys, particularly the local lattice distortion (LLD) and the short-range order (SRO). The LLD will increase the lattice resistance to dislocation slip, thereby increasing the strength of the material. Furthermore, ab initio calculations suggest that LLD significantly contribute to the thermal stability, even outweighing the entropy effects for alloys with more than three components. Controlling the LLD in RHEAs therefore appears to be a promising route to optimize both thermal stability and mechanical properties. However, previous studies suggest that the degree of LLD is not easily predictable and does not necessarily increase with the number of elements. There is thus a fundamental lack of understanding which prevents the use of knowledge-based design of RHEAs with tailored LLD.

The use of neutron scattering, in particular the use of total scattering and pair distribution function (PDF) analysis provide unique possibilities to understand these phenomena. So, the current research project aims at development and application of total neutron scattering techniques for characterization of refractory high entropy alloys. By performing in-situ measurements at elevated temperatures the effects of LLD and SRO on the thermal stability and mechanical properties of alloys being developed for next generations high temperature applications.