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Materials Science at Oregon State University

Self-organization of nanoscale void superlattice under radiation

Date: Thursday, Nov 16th
Presenter: Dr. Yongfeng Zhang, Idaho National Laboratory


Nanoscale self-organization has led to the formation of a variety of two-dimensional (2D) and three-dimensional (3D) patterned structures such as nanoparticle superlattices, quantum dots, nanodroplets, and void and gas bubble superlattices. Such patterned nano-structures have significant scientific merits and great technological importance for their novel physical properties. As a powerful tool to create far-from-equilibrium environments, radiation provides an opportunity to generate unique self-organization phenomena in pure metals and alloys, such as nanoscale compositional patterning in immiscible alloys, patterning of defect clusters and loops, and void/bubble superlattices. To tailor the design of such self-organized nano-structures requires a fundamental understanding of the driving mechanisms, which are yet to be developed for void/bubble superlattices. Using rate theory analysis and kinetic Monte Carlo and phase field simulations, in this work the nature of void superlattice formation is discerned, which enables accurate predictions of superlattice structure and parameter. The theory developed can provide guidelines for designing target experiments to tailor desired microstructure under irradiation. It may also be generalized for situations beyond irradiation, such as spontaneous phase separation with reaction. The research is supported by the Department of Energy, Office of Science, Basic Energy Science project “The Role of Anisotropy on the Self-Organization of Gas Bubble Superlattices”.

Dr. Yongfeng Zhang is currently a staff scientist at Idaho National Laboratory (INL), where he serves as the Lead of the Computational Microstructure Science group and the principle investigators of two work packages under the Department of Energy NEAMS program and the USHPRR program. Dr. Zhang graduated from Rensselaer Polytechnic Institute with a PhD degree in Mechanical Engineering, Aug. 2009, and joined INL after that. His and his group’s research focuses on atomistic to mesoscale modeling and simulation of the concurrent evolution of microstructure and properties in materials used in nuclear environments combining high temperature, stress, irradiation and corrosive species. The phenomena of interest include radiation damage, swelling, phase transformation, corrosion and degradation in mechanical and thermal properties in various fuels, claddings, and structural materials. Dr. Zhang has authored or co-authored over 40 peer-reviewed journal publications and delivered over 30 conference presentations. At INL, he received the Exceptional Contribution Program Award in 2014 and 2016, and the Laboratory Director’s Award for Leadership in 2017.