首页 » 锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷
Dr. Dong Liu Department of Materials University of Oxford
Title: In situ Characterisation of the Mechanical Behaviour of Energy Materials under Extreme Conditions
Materials with multiple length-scale structures are a fascinating yet critical class of material that have characteristic dimensions spanning from nano- to macro-scales. These materials have enormous potential for nuclear and energy applications as they can display unique properties such as combinations of strength and toughness at ambient to elevated temperatures.
Taking nuclear-grade graphite as an example, which is a porous graphite composite used as the moderator and major structural component in UK power reactors, I will talk about mechanical testing under two extreme conditions: fast neutron irradiation and elevated temperatures (1000°C) using in situ micro-mechanical testing inside a scanning electron microscope and in situ high temperature 3D X-ray computed tomography, respectively. It was found that this material displays unusual higher strength and fracture toughness at elevated temperatures due to the relaxation of residual stresses.
Further examples on the failure modes of several ceramic-based composites tested in situ at elevated temperatures up to 1200°C will be covered briefly.
Dr. Dong Liu is currently a EPSRC (Engineering and Physical Sciences Research Council) Research Fellow, Royal Commission for the Exhibition of 1851 Brunel Research Fellow, and Mansfield College Junior Research Fellow at the University of Oxford (UK), and a research affiliate to the Lawrence Berkeley National Lab (USA). She obtained her Ph.D. at the University of Bristol (UK) in 2012 on the measurement of residual stresses and mechanical properties in environmental and thermal barrier coatings. She then worked as a postdoctoral researcher on the deformation and fracture of quasi-brittle materials such as cement, gypsum plaster composites and nuclear graphite before moving to Oxford.
Her current project is to challenge the in situ mechanical testing on nuclear and energy materials at multiple length-scales (from micro- to macro-size), and under extreme conditions such as irradiation and elevated temperature. The materials of interest include graphite materials and carbon composites, ceramic-based composites, MAX-phase ceramics, environmental and thermal barrier coatings, nano-structured steels and GaN-diamond composite materials for electronic devices.