Dr. Jiao is an Associate Professor at the Department of Mechanical Engineering, The Hong Kong Polytechnic University (PolyU). He received his PhD from City University of Hong Kong in 2014 and worked as a postdoc at CityU in 2015 and at MIT in 2016. He joined PolyU as an Assistant Professor in 2017 and was promoted to Associate Professor with tenure in 2022.
Dr. Jiao’s research interests focus on the development of advanced structural materials, including ultra-high strength steels, high-entropy alloys, high-temperature superalloys, intermetallics, and nanostructured alloys. His work was published in high-profile journals such as Science, Nature Communications, Materials Today, and Acta Materialia. He serves as an associate editorial board member of Materials Research Letters and received twice the Acta Materialia & Scripta Materialia Outstanding Reviewer Award.
Nano-lamellar materials with ultrahigh strengths and unique physical properties are of technological importance for structural applications. However, these materials generally suffer from low tensile ductility, which severely limits their practical utility. In this talk, we show that markedly enhanced tensile ductility can be achieved in coherent nano-lamellar high-entropy alloys, which exhibit an unprecedented combination of over 2 GPa yield strength and 16% uniform tensile ductility. The ultrahigh strength originates mainly from the lamellar boundary strengthening, whereas the large ductility correlates to a progressive work-hardening mechanism regulated by the unique nano-lamellar architecture. The coherent lamellar boundaries facilitate the dislocation transmission, which eliminates the stress concentrations at the boundaries. Meanwhile, deformation-induced hierarchical stacking-fault networks and associated high-density Lomer-Cottrell locks enhance the work hardening response, leading to unusually large tensile ductilities. The coherent nano-lamellar strategy can potentially be applied to other alloys and open new avenues for designing ultrastrong-yet-ductile materials for technological applications.