时 间： 2019年6月13日9:00-11:00
报告题目：Designing and Engineering amorphous ceramic composites for extreme conditions through tailoring nanosized heterogeneities
Strong, ductile, and irradiation tolerant structural materials are in urgent demand for improving the safety and efficiency of advanced nuclear reactor. Amorphous ceramics could be very promising candidates for high radiation tolerance since they do not contain conventional crystal defects that are induced in crystalline materials under irradiation. However, amorphous ceramics can exhibit ‘brittle-like’ behavior due to flow instability though they exhibit superior thermo-mechanical properties with respect to strength and hardness, creep and oxidation, and structural stability at high temperatures and under irradiation. We proposed to realize the strength-ductility-irradiation tolerance combination of amorphous ceramic composites (ACCs) through tailoring nanosized heterogeneities. Principles for the design of such ACCs are urgently demanded. First, there is a lack of comprehensive understanding of heterogeneities-induced plasticity, heterogeneities-suppressed flow instability, and heterogeneities-enhanced irradiation tolerance in amorphous ceramics. Second, there is a lack of selection principles for metal constituents with respect to ACCs with the selected non-metal constituents. Metal elements that will be mixed with amorphous ceramics should prefer to form nanosized metal-rich clusters (or nanosized heterogeneities) in ACCs. Moreover, the phase structure and properties of the heterogeneity should be able to be modified by synthesis and annealing conditions. We built upon these principles through an iterative design process that integrates theory, modeling, and experiments. By averting plastic flow localization and enhancing irradiation tolerance, we impart to ACCs the ability to undergo both uniform plastic deformation and irradiation tolerance, markedly advancing their potential for use in nuclear industry as core structural materials.
Dr. Jian Wang is a full professor of Materials and Mechanical Engineering at the University of Nebraska-Lincoln. He received his Ph.D from Rensselaer Polytechnic Institute, Troy, NY, USA, in 2006, and worked at Los Alamos National Laboratory (LANL) as technical staff member for 9 years. His research focuses on quantitatively exploring the structure-properties relations of structural and nanostructured materials using multi-scale theory, modeling and experimental methods and techniques. He was awarded the LANL Distinguished Postdoctoral Performance Award (2009), the LDRD/Early Career Award (2011), two LDRD-ER Awards (2013), TMS MPMD Young Leader Award (2013), International Plasticity Young Research Award (2015), Journal Outstanding Reviewer Awards for Scripta Materialia (2016), Modelling and Simulation in Materials Science and Engineering (2016), and Acta Materialia (2017), and Materials Today 2018 Rising Star Award in the category of Materials Genome Innovation (2018). He served as Editorial Board of International Journal of Plasticity (2015~), Scientific Reports (2016~), and several others. He has published more than ~250 peer-reviewed papers (> 9000 citations and H-index = 58, 25 papers selected as Hottest Articles in Materials Science, and 7 papers featured as Journal cover), and delivered 100+ invited/keynote presentations.