Dr. Yanwen Zhang is a Professor and Canada Excellence Research Chair in Radiation Impact on Energy and Advanced Technologies at Smith Engineering, Queen's University. She previously held positions at Idaho National Laboratory, Oak Ridge National Laboratory with a faculty appointment at the University of Tennessee, Pacific Northwest National Laboratory, and Uppsala University in Sweden. She earned two PhDs from Lund University (Sweden) and form Beijing Normal University (China).
Dr. Zhang’s research focuses on defect dynamics, ion beam modification and radiation effects, aiming to tailor these processes for targeted complex materials’ functionality and properties. She was the recipient of the 2005 Presidential Early Career Award for Scientists and Engineers, the highest honor bestowed by the U.S. government on outstanding scientists and engineers beginning their independent careers. She directed an Energy Frontier Research Center for Energy Dissipation to Defect Evolution from 2014-2020 to advance the understanding of energy dissipation mechanisms in complex alloys, with ultimate aims to control the evolution of defects in structural materials. Dr. Zhang has over 420 journal articles with close to 14,000 citations and an H-index of 53 based on the Web of Science and over 17,600 citations and an H-index of 62 based on Google Scholar. She has over 100 invited presentations and 65 other presentations at national and international scientific conferences, workshops, research institutions, and universities. Dr. Zhang is a Fellow of American Ceramic Society.
Education and degrees
Lund University, Sweden Docent 2004 Nuclear Physics
Beijing Normal University, China Ph.D. 1999 Materials Science and Engineering
Lund University, Sweden Ph.D. 1998 Nuclear Physics
Beijing Normal University, China M.S. 1993 Materials Science and Engineering
Beijing Normal University, China B.S. 1990 Solid State Physics
Employment
May 2024 – present: Canada Excellence Research Chair in Impact of Radiation in Energy and Advanced Technologies, at Department of Mechanical and Materials Engineering (MME), Smith Engineering, Queen's University.
Nov. 2022 – May 2024: Directorate Fellow, Condensed Matter Physics, Energy and Environment Science & Technology, Idaho National Laboratory (INL).
2010 – Nov. 2022: Distinguished Research and Development (R&D) staff (since 2015), Materials Science and Technology Division, Oak Ridge National Laboratory (ORNL); Joint Faculty in Materials Science and Engineering (MSE), University of Tennessee (UTK). Deputy Director of the UTK Ion Beam Materials Laboratory (http://ibml.utk.edu/), responsible for training students and postdocs and management of routine operations.
2003 – 2010: Staff Scientist/Senior Research Scientist, Pacific Northwest National Laboratory (PNNL).
2000 – 2002: Assistant Professor, Division of Ion Physics, Uppsala University, Sweden.
1999 – 2000: Postdoctoral researcher, Division of Ion Physics, Uppsala University, Sweden.
Dr. Zhang’s research focuses on fundamental and applied aspects of equilibrium and non-equilibrium defect dynamics, ion beam modification and radiation effects in materials, with an emphasis on how energy transport processes can be modified and applied to tailor functionality and properties of complex materials.
Exploring energy transport in materials across various time and length scales, along with nonlinear defect dynamics controlled by chemical disorder at the electronic and atomic levels, paves the way for materials discovery. This research studies the emergence of complex macroscopic phenomena from microscopic interactions, reveals defect states under non-equilibrium conditions, and investigates material behavior under dimensional constraints. Our work not only uncovers the potential of electronic and atomic disorder for enhancing material properties but also drives the development of functional materials through the creation of novel defect states and structures. Additionally, it informs the design of structural materials for advanced nuclear applications. These advancements have broader implications for uncovering exotic material properties and enhancing our understanding of condensed matter physics.
Understanding materials under extreme conditions is essential for societal needs such as energy production, environmental preservation, and national security, offering potential for groundbreaking discoveries. Extreme conditions include high temperature, pressure, radiation, and corrosive environments. Ion bombardment induces localized extremes, affecting electronic and atomic structures. This process generates defects, alters energy barriers, and enhances diffusion. Uncovering, predicting, and ultimately controlling energy transport and the response to external perturbations (e.g., radiation, mechanical loading) in crystalline structures are grand challenges across diverse fields in materials science and critical to many energy-related technologies. To design better materials to meet societal needs, an in-depth understanding of the underlying physics and chemistry of simple and complex systems at the level of electrons and atoms, beyond the typically decoupled studies, is essential. Some specific research directions are outlined below.
The role of electrons in damage evolution and structural deformation in ceramics and alloys The complexity of the electronic and atomic structures can bring materials to extreme and often transient regimes where practical experience and fundamental knowledge are limited. Extreme disturbances can lead to unexpected material behavior, posing challenges for accurate predictions. Modifying material composition, especially in high-entropy ceramics (HECs, such as high-entropy borides, carbides, nitrides, and oxides) and high-entropy alloys (HEAs), offers unprecedented tunability of transformative responses. Lattice strains resulting from random elemental occupations are influenced by local electronic deformability, impacting defect formation and migration energies. Radiation studies in ceramics reveal varied responses due to the interplay between short-range covalent and long-range ionic forces. While metallic bonding in transition-metal alloys is conventionally described as positively charged nuclei surrounded by a cloud of valence electrons, recent studies have highlighted the presence of directional bonding and valence charge redistribution. Nonetheless, our understanding of ionization effects remains limited. These limitations underscore the need for further research to uncover new insights and opportunities for discovery.
Complex Materials with Mixed Chemical Bonds under Irradiation Radiation effects on materials have been extensively studied, revealing diverse responses to defect production and damage accumulation. For example, similar oxides can display contrasting radiation performance, suggesting the importance of balancing short-range covalent and long-range ionic forces to resist amorphization. While debated, findings indicate that short-range covalently bonded semiconductors readily amorphized, whereas metals and metal alloys with long-range metallic bonding tend to resist it. However, the distinction between chemical bonds is less clear in complex materials. Our research focuses on bond characteristics and electronic deformability in ionically/covalently bonded ceramics with multiple cation substitutions, as well as in complex concentrated alloys (CSAs) or HEAs. Through modeling and experimental methods, we aim to uncover fundamental insights into materials with mixed bonding characteristics under irradiation.
Tunable chemical disorder in complex metallic alloys to tailor radiation performance The microstructural changes observed in conventional alloys under radiation over the past half-century are consequences of complex interactions. While some alloys outperform metal counterparts in radiation resistance, understanding the underlying mechanisms at the most fundamental level (electrons and atoms) remains incomplete. CSAs exhibit intricate chemical disorder, offering a range of tunable characteristics. Modifying defect dynamics by tuning chemical disorder under non-equilibrium conditions leads to improved understanding of cascade evolution mechanisms, damage processes, and radiation energy dissipation. The impacts of differences in valence electron counts, electronic structures, magnetic moments, atomic volume, and mass can be assessed by controlling irradiation conditions. Leveraging accumulated knowledge from traditional alloys and recent advances in additive manufacturing is driving significant breakthroughs. Developing advanced alloys that depend on both chemical disorder and precisely engineered microstructures for specific properties represents a critical frontier in alloy development.
Tunable chemical disorder in high entropy borides, carbides and nitrides to tailor materials’ property and radiation performance Insights into the complex electronic and atomic interactions under extreme energy deposition enable the design of radiation-tolerant materials and prediction of performance in harsh environments. Thus, understanding the role of tunable chemical disorder on radiation effects and mechanical properties in high-entropy borides, carbides, and nitrides, as well as mixed compositions, is essential. This knowledge will expand our ability to design materials and predict performance in severe radiation environments encountered in next generation nuclear applications, high-energy accelerators, and space exploration, as well as pave the way to better control fundamental processes and design new material functionalities for advanced technologies.
Understanding defect dynamics in complex alloys to link strong mechanical strength, superior radiation performance, and/or greater superconducting properties Research on structural and concentrated alloys has primarily focused on phase stability and mechanical properties, with less attention given to their dynamic responses under radiation-induced nonequilibrium conditions. Mechanical strength in many alloys is linked to dislocation properties, influenced by bond switching and dynamic crack propagation. In CSAs containing various 3d transition metals, bond distortion and breaking are affected by d-band filling and lattice symmetry. CSAs with significant differences in electronegativity may exhibit enhanced radiation performance and superconductivity. However, the mechanisms underlying these phenomena are not fully understood. Electronic and magnetic contributions to defect production and solid-solution strength in CSAs composed of different TMs remain unclear. Understanding defect dynamics in complex alloys may elucidate their mechanical strength, radiation resistance, and superconducting properties.
Scientific understanding and technical advances often go hand-in-hand in developing semiconductors and functional materials. Current knowledge of dopant activation, defect production, and microstructure evolution in functional ceramics and ultra-wide-bandgap semiconductors under ionizing irradiation is in its infancy. A unified understanding of underlying mechanisms, especially in utilizing ion–electron collisions and extreme ionization to modify functionality, remains lacking. Research in this direction can initiate industrial-academic collaborations.
Greater device performance via thermal equilibrium and athermal nonequilibrium processes Ultra-wide-bandgap oxides and conventional wide-bandgap semiconductors are promising candidates for power electronics, optoelectronics, and electronic devices for harsh environment applications (e.g., nuclear, high-energy physics experiments, and space applications). While we have worked on Si, GaAs, InP, and SiC semiconductors in the past, the current effort aims to understand damage production and evolution mechanisms and dopant behaviors in wide-bandgap materials and to unravel the intricate correlations between atoms and electrons by altering bandgap and covalent/ionic characteristics. The significant implications include the use of non-equilibrium ion beam techniques to eliminate damage from implantation doping in advanced device fabrication processes, to develop ion beam processing as a key enabling tool for wide-bandgap semiconductor technology, and to functionalize thin films or surfaces.
Functionalities modification via nonequilibrium processes Historically, the focus has been on separate aspects of energy processes, such as nuclear energy deposition and electronic energy deposition. However, recent advancements have highlighted the importance of understanding the varying roles of spatial and temporal processes in the response of functional materials to energy deposition and transfer. This understanding is essential for developing new materials based on novel defect states and structures far from equilibrium. By controlling and exploiting nonequilibrium electronic and atomic interactions, promising advancements can be made in energy and information-related technologies. Our goal is to understand functionalities modification by charged particle-induced nonequilibrium processes, utilizing ionizing ion and electron beams to reorder or amorphize the local atomic arrangement. Through simulations and experiments varying nuclear energy loss, electronic energy loss, and the electronic-to-nuclear energy loss ratio, we aim to investigate and understand athermal effects. The insights facilitate the application of guided ionizing beams to nanopatterning of functional phases with atomic precision and engineering of complex interfaces.
Improved x-ray, gamma, and neutron detectors are essential for various fields, including national security, medical, and nuclear physics applications. However, progress on scintillator detectors has been slow due to limited understanding of nonproportionality, energy transport, and energy resolution. Conventional methods focusing solely on studying nonproportionality across different materials are unlikely to break through current knowledge barriers and discover new or advanced scintillator materials. A novel approach involves studying scintillation response to ion excitation across various ion energies and densities in various scintillators. By leveraging advanced film deposition or crystal growth techniques and ion-solid interactions, this research aims to predict scintillation performance. Using thin films/crystals and ion-induced modification or dopant implantation, we will identify and quantify contributions to nonproportionality and light yield. This approach, combined with theory/modeling, seeks to develop a predictive model for nonproportional response, facilitating accelerated and efficient detector material discovery while advancing our understanding of scintillation physics.
Dr. Zhang has authored or co-authored over 420 refereed journal articles and 9 book chapters, and served as the editor of 1 book. Her work has garnered close to 14,000 citations and an H-index of 53 according to the Web of Science, and over 17,600 citations with an H-index of 62 based on Google Scholar. A comprehensive list of publications is provided below.
Are you an ambitious and passionate student eager to pursue a graduate degree? Are you fascinated by the world of materials research? Unlock your potential and contribute to cutting-edge research that shapes the future of materials science!
Dr. Zhang is actively seeking talented individuals at both the Master's and PhD levels, as well as postdoctoral researchers, to join her dynamic research team. We also have a couple of undergraduate research positions. Take the first step towards an exciting academic and research career by joining Dr. Zhang's research group at Queen's University. Please review her publications and explore her research interests in nuclear materials and materials science in general.