Speaker: Dr. Dong (Lilly) Liu
University of Bristol, UK
Date: 07th October 2023 (18:00-19:30 IST)
Advanced energy materials used in nuclear and aerospace areas often have multiple length-scale structures displaying unique properties such as combinations of strength and toughness at elevated temperatures. Nuclear graphite, which is used as the moderator and structural component in operating reactor and future designs, have been found to exhibit an increased strength and toughness at 1000-1100°C compared to room temperature. Using a range of real-time imaging, diffraction and spectroscopy-based techniques, this behaviour was correlated to the relaxation of residual stresses. Related materials, such as low- and high-density Pyrolytic Carbon (PyC), were used to coat spherical fuel kernels in TRISO (tri-structural isotropic) particle. These PyC layers, together with the SiC layer in TRISO, were found to possess notable magnitude of residual stresses (measured by focussed-ion-beam digital-image-correlation method) and impact the particles’ high temperature behaviour as well as irradiation-induced dimensional changes. Lastly, ceramic-matrix composites (aerospace components and accident tolerant fuel cladding) have demonstrated very different toughening mechanisms from ambient when fractured at 1100-1250°C. Implications of these observations on the materials design optimisation will be discussed.
Bio-data of speaker:
Dr. Dong (Lilly) Liu is currently an Associate Professor at the School of Physics, University of Bristol and Lead of the Materials and Device Theme. She is also Head of the Experimental Mechanics of Advanced Materials group (EMAM). Dr. Liu joined the University of Bristol as Lecturer in July 2018 from Oxford University (2015-2018) where she held an independent 1851 Exhibition Royal Commission Fellowship (Brunel) and an EPSRC Postdoctoral Research Fellowship. Dr. Liu was also awarded a Junior Research Fellowship at Mansfield College (2016-2018) while at the University of Oxford.
Dr. Liu is to re-join the University of Oxford as an Associate Professor in Engineering Science Department and Tutorial Fellow in Trinity College in January 2024. Dr. Liu has published a co-authored book (Ritchie & Liu, Introduction to Fracture Mechanics, 2021, Elsevier), several book chapters and more than 50 journal publications including Science, Nature Communications and Carbon.
InSIS and Center for Structural Integrity of Safety Critical Systems, IIT Madras