北京大学力学与工程科学学院 

报告人：Dong (Lilly) Liu

Department of Engineering Science

University of Oxford

时  间：8月7日（周四）10:00-11:30

地  点：北京大学新奥工学大楼3048会议室

Abstract: 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: Prof. Dong (Lilly) Liu joined the University of Oxford in January 2024, as an Associate Professor in the Engineering Science Department and Tutorial Fellow in Trinity College. Prior to this, she was an Associate Professor at the University of Bristol where she was Lead of the Materials and Device Theme in the School of Physics, and Head of the Experimental Mechanics of Advanced Materials group (EMAM). Prof. Liu’s research interest lies in the area of multiple-scale nano-/microstructural and mechanical characterization of advanced engineering materials in extreme conditions, including ion/neutron/proton irradiation, elevated temperatures and cryogenic environments with applications across nuclear fission, fusion, aerospace, power electronics & RF devices, hydrogen storage, space and concentrated solar power. Prof. Liu has published a co-authored textbook Ritchie & Liu, Introduction to Fracture Mechanics, 2021, Elsevier, several book chapters and >60 journal/conference papers.

Prof. Liu serves on several international technical committees, including the ASTM C28.07 Committee (Ceramic Matrix Composites), Composite Materials Handbook Standards (CMH-17) Ceramic Matrix Testing Working Group and the IOM3 Ceramic Science Committee. At TMS (The Minerals, Metals & Materials Society, USA), she was appointed the Program Committee Representative to the SMD Council (Structural Materials Division) for 2024-2027, member of the TMS Education Committee (2024-2027) and TMS Nuclear Materials Committee MiNES Liaison (Materials in Nuclear Energy Systems, USA) for 2023-2026. She is currently the Chair of the Awards Committee and Incoming Secretary of the Engineering Ceramics Division in the American Ceramic Society (ACerS), as well as ACerS’ UK Chapter Chair. Prof. Liu is a member of the EPSRC’s Research Infrastructure Strategic Advisory Team (SAT) in the UK.

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