Yijia Gu, a Ph.D. student working in...
Assistant Professor of Materials Science and Engineering and the
Norris B. McFarlane Faculty Professorship
202A Steidle Building
Allison Beese received her B.S. degree in Mechanical Engineering from Penn State University. Following her undergraduate studies, she was employed at Lockheed Martin’s Knolls Atomic Power Laboratory, where she designed large scale experiments and performed failure analysis of nuclear power plant components. She then entered graduate school at MIT, where she conducted research in Professor Tomasz Wierzbicki’s Impact and Crashworthiness Laboratory, and was awarded a Department of Defense National Defense Science and Engineering Graduate Fellowship. She earned her M.S. and her Ph.D. degrees in Mechanical Engineering with a minor in Biomechanics at MIT.
Her doctoral research involved experimental characterization and modeling of the large deformation behavior of anisotropic steel sheets undergoing strain-induced phase transformation. Dr. Beese spent two years as a postdoctoral fellow in Professor Horacio Espinosa’s Micro and Nanomechanics Laboratory at Northwestern University, where she experimentally studied fabrication-structure-property relationships of both carbon based nanomaterials, using microelectromechanical systems (MEMS)-based testing techniques in situ a transmission electron microscope (TEM), and macroscopic materials derived from nanoscale carbon constituents.
She joined the Materials Science and Engineering faculty at Penn State in July 2013.
Dr. Beese’s research interests are in experimental and computational multiscale mechanics of materials ranging from metals to composites. Her research focuses on developing experimental methods to elucidate the connections between the evolving microstructure and the macroscopic deformation, dissipation, and failure properties of materials. Using the experimental results, predictive large deformation and failure models can be developed.
One particular material of interest is steel, which remains one of the most widely used structural materials, and new grades of steels are constantly being developed. Advanced High Strength Steels (AHSS) are a particularly attractive class of steels, as they offer increased strength without sacrificing ductility, lending themselves to the application in lightweight vehicle structures where high mass specific energy absorption is critically important. However, in order to fully exploit the benefits of these AHSS, it is imperative to understand the mechanisms of deformation and failure in order to develop physically-based predictive computational models that can be used in the forming and crash predictions of large scale structural components.
Metastable austenitic steels belong to the class of AHSS. They offer a combination of high strength and ductility, which is attributed to their characteristic deformation-induced phase transformation. Dr. Beese has developed experimental methods to quantify the evolution of the microstructure non-destructively with applied large deformation and varying stress state, resulting in the development of a finite-deformation anisotropic plasticity model that describes the constitutive behavior of stainless steel sheets undergoing phase transformation from austenite to martensite. Current research is focused on expanding these techniques and models to different AHSS, and experimentally and computationally describing the fracture properties of these AHSS.
She also has experience in the design and testing of carbon-based composite materials, where a macroscale composite is composed of nanoscale constituents: either carbon nanotubes or graphene oxide. These materials are investigated toward the development of high-performance composites for armor applications.
Beese, A.M., D. Papkov, S. Li, Y. Dzenis, and H.D. Espinosa. In situ TEM elucidation of diameter and structure effects on mechanical properties of electrospun carbonized fibers. Carbon, vol. 60, pp. 246-253, 2013.
Beese, A.M., S. Sarkar, A. Nair, M. Naraghi, Z. An, A. Moravsky, R.O. Loutfy, M.J. Buehler, S.T. Nguyen, and H.D. Espinosa. Bio-inspired Carbon Nanotube-Polymer Composite Yarns with Hydrogen Bond-Mediated Lateral Interactions. ACS Nano, vol. 7(4), pp. 3434-3446, 2013.
Beese, A.M., and D. Mohr. Anisotropic Plasticity Model Coupled with Lode Angle Dependent Strain-Induced Transformation Kinetics Law. Journal of the Mechanics and Physics of Solids, vol. 60(11), pp. 1922-1940, 2012.
Beese, A.M., and D. Mohr. Effect of Stress Triaxiality and Lode Angle on the Kinetics of Strain-induced Austenite-to-Martensite Transformation, Acta Materialia, vol. 59 (7), pp. 2589-2600, 2011.
Beese, A.M., and D. Mohr. Identification of the Direction-dependence of the Martensitic Transformation in Stainless Steel using In-situ Magnetic Permeability Measurements, Experimental Mechanics, vol. 51(5), pp. 667-676, 2011.
Assistant Professor of Materials Science and Engineering
N-339 Millennium Science Complex
Dr. Nasim Alem received her B.S. degree in Metallurgical Engineering from Sharif University of Technology, Tehran, Iran and her M.S. degree in Materials Science and Engineering from Worcester Polytechnic Institute in Worcester, MA. She did her PhD in Materials Science Department at Northwestern University in 2008. Nasim has been a postdoctoral researcher in the Physics Department at University of California Berkeley and National Center for Electron Microscopy at Lawrence Berkeley National Lab, before joining The Pennsylvania State University as an assistant professor in 2013.
Alem’s PhD research was focused on the nanoscale mechanics and deformation behavior of confined interphases in multilayered metal-ceramic systems where she used transmission electron microscopy to investigate the role of chemistry, and size scale on the plasticity and deformation mechanism at small size scales. Alem’s postdoctoral research was focused on probing the atomic structure of defects and edges and their relaxations in two-dimensional crystals with the utilization of Ultra-high Resolution aberration-corrected transmission electron microscopy. During her postdoc, Alem also studied the formation, growth and dynamics of defects in two dimensional crystals, i.e. graphene and hexagonal boron nitride under insitu heating and electrical biasing conditions. Alem joined the Materials Science and Engineering Department at Penn State on March 2013.
Defects can modulate the electronic properties of crystals by introducing empty states within their band gap. When exposed to chemical functional groups, defects can trap molecules and adatoms resulting in significant changes to the catalytic and sensing properties of the crystal. They can also act as nucleation sites for dislocations leading to deformation when the crystal is placed under stress. Therefore it is crucial to understand the atomic and chemical structure of the defects within crystals before they can be nano-engineered for functional devices. Modifying the atomic structure can significantly tailor materials properties making them suitable for a variety of applications such as energy and catalysis.
Alem’s research focuses on the structurally driven aspects that can affect the resulting physical, chemical and mechanical properties of crystals, especially those used in catalysis and energy; where we probe and understand the effect of defects, vacancies, interfaces and grain boundaries on the chemical, physical and electronic properties of materials using imaging and spectroscopy techniques in transmission electron microscopy. Our group is also interested in the evolution of defects, edges, grain boundaries and interfaces and nanoscale mass transport in nanostructures under thermal and electrical loading using in situ TEM.
Ashley L. Gibb, Nasim Alem, Jianhao Chen, Kris Erickson, Jim Ciston, Abhay Gautam, Martin Linck, Alex Zettl, “Atomic Resolution Transmission Electron Microscopy of Grain Boundaries in Chemical Vapor Deposition Hexagonal Boron Nitride”, JACS 135 (18), 6758–6761, 2013.
Nasim Alem, Quentin Ramasse, Che Seaborne, Oleg V Yazyev, Kris Erickson, Michael Sarahan, Andrew J Scott, Steve G Louie, Alex Zettl; Subangstrom edge relaxations probed by electron microscopy in hexagonal boron nitride; Physical Review Letter, PRL 109, 205502 –November 2012
Nasim Alem, Rolf Erni, Christian Kisielowski, Marta D. Rossell, Peter Hartel, Bin Jiang, Will Gannett, Alex Zettl, “Vacancy Growth and Migration Dynamics in Atomically Thin Hexagonal Boron Nitride Under Electron Beam Irradiation” Physica Status Solidi - RRL 5, 8, 295–297, July 2011 (featured in “Materials Views”).
Kris Erickson, Ashley Gibb, Alex Sinitskii, Michael Rousseas, Nasim Alem, James Tour, Alex Zettl; Longitudinal Splitting of Boron Nitride Nanotubes for the Facile Synthesis of High Quality Boron Nitride Nanoribbons; Nano Letters 11 (8), pp. 3221-3226, (2011). (Featured in “First Science” and “Today at Berkeley Lab”).
Nasim Alem, Rolf Erni, Christian Kisielowski, Marta D Rossell, Peter Hartel, Bin Jiang, Will Gannett, Alex Zettl; Vacancy Growth and Migration Dynamics in Atomically Thin Hexagonal Boron Nitride Under Electron Beam Irradiation; Physica Status Solidi – RRL 5 (8), pp 295–297, (2011) (featured in “Materials Views”).
Nasim Alem, Oleg V Yazyev, Christian Kisielowski, Peter Denes, Uli Dahmen, Peter Hartel, Max Haider, Martin Bischoff, Bin Jiang, Steve G Louie, Alex Zettl; Probing the Out-of-plane Distortions to Single Point Defects at the Picometer Scale in Atomically Thin Hexagonal Boron Nitride; Physical Review Letters 106, 126102, (2011).
Kris Erickson, Rolf Erni, Zonghoon Lee, Nasim Alem, Will Gannett, Alex Zettl; Determination of the Local Chemical Structure of Graphene Oxide and Reduced Graphene Oxide; Advanced Materials 22, pp. 4467–4472, (2010).
Rolf Erni, Marta Rossell, Manh-Thuong Nguyen, Stephan Blankenburg, Daniele Passerone, Peter Hartel, Nasim Alem, Kris Erickson, Will Gannett, Alex Zettl; Stability and Dynamics of Small Molecules Trapped on Graphene; Physical Review B 82, 165443, (2010).
Will Regan, Nasim Alem, Benjamin Alemán, Baisong Geng, Çağlar Girit, Lorenzo Maserati, Feng Wang, Michael Crommie, Alex Zettl; A Direct Transfer of Layer-Area Graphene; Applied Physics Letters 96, 113102, (2010).
Nasim Alem, Rolf Erni, Christian Kisielowski, Marta Rossell, Will Gannett, Alex Zettl; Atomically Thin Hexagonal Boron Nitride Probed by Ultra-high-resolution Transmission Electron Microscopy; Physical Review B, 80 (15), 155425, (2009) (editor’s suggestion, featured in “Physics”).
Dr. Gopalan received his B.Tech. in Metallurgical Engineering from the Indian Institute of Technology, Chennai, in 1989, and his Ph.D. in Materials Science and Engineering from Cornell University in 1995. He was a postdoctoral scholar in the Electrical and Computer Engineering Department at the Carnegie Mellon University from 1995-1996, and was subsequently awarded a director funded postdoctoral fellowship at the Los Alamos National Laboratory, where he performed research on ferroelectrics and electro-optics till 1998.
He joined Pennsylvania State University as an assistant professor in December 1998, and became a full professor in 2007. He has been awarded the National Science Foundation CAEEER award (2000), Robert R. Coble Award from the American ceramics Society (2002), Corning Faculty fellowship in Ceramic Sciences (2004), National Research Council Faculty Fellowship (2004), Wilson award for excellence in research (2005), Eshbach Faculty Fellow at the Northwestern University (2007), Richard M. Fulrath award from the American ceramics Society (2009).
He is the associate director of the Center for Optical Technologies since 2003, has served on the editorial board of the Annual Reviews of Materials research since 2004, and served as the Chairman of the User Executive Committee for the Center for Nanophase Materials Science, Oak Ridge National Laboratory, in 2010-11. Gopalan has published over 150 papers, and has written five book chapters on ferroelectric complex oxides, nonlinear optics, optical metamaterials, and scanning probe microscopy.
Our research focuses on the science and technology of nonlinear optical materials. The work straddles materials science, physics, and optical engineering. We have three areas of current interest:
Experimental tools include ultrafast femtosecond lasers, electro-optics and fiber optics, scanning probe microscopies, dielectric and magnetic measurements, clean room, cryogenics, and simulations based on home-written MATLAB as well as commercial codes.
Multiferroics enable electrical control of magnetic devices, and vice versa, and dual electrical-magnetic storage media. Nonlinear optical devices are targeted for optical communications and infrared applications. The vision of hybrid semiconductor-metal-silica structures is all-fiber optoelectronics, where light generation, modulation and detection can be performed within a fiber.
V. Gopalan, D. B. Litvin, “New symmetries in crystals and handed structures,” Nature Materials , DOI: 10.1038/nmat2987 (2011). http://www.nature.com/nmat/journal/vaop/ncurrent/abs/nmat2987.html
J. R. Sparks, R. He, Noel Healy, M. Krishnamurthi, A. C. Peacock, P. J.A. Sazio, V. Gopalan, and J. V. Badding, “Low loss ZnSe Optical Fiber Waveguides,” Advanced Materials, 23, 1647-1651 (2011).
A. Vasudevarao, A. N. Morozovska, I. Grinberg, S. Bhattacharya, Y. Li, S. Jesse, P. Wu, K. Seal, S. Choudhury, E.A. Eliseev, S. Svechnikov, D. Lee, S. Phillpot, L.Q. Chen, A. M. Rappe, V. Gopalan and S.V. Kalinin, “Correlated polarization switching in the proximity of a 180 degree domain wall,” Phys. Rev. B. 82, 024111 (2010).
J. H. Lee, L. Fang, E. Vlahos, X. Ke, Y. W. Jung, L. Fitting Kourkoutis, J.W. Kim, P. Ryan, T. Heeg, M. Roeckerath, V. Goian, M. Bernhagen, R. Uecker, P. C. Hammel, K. M. Rabe, S. Kamba, J. Schubert, J. W. Freeland, D. A. Muller, C. J. Fennie, P. Schiffer, V. Gopalan, E. Johnston-Halperin & D. G. Schlom, “Creating a Strong Ferroelectric Ferromagnet via Spin-Phonon Coupling,” Nature 466, 954 (2010).
I. A. Temnykh, N. F. Baril, Z. Liu, J. V. Badding, V. Gopalan, “Optical multistability in a silicon-core silica-cladding fiber,” Optics Express, 18, 5305-5313 (2010).
Tarasankar DebRoy obtained his Ph.D. from Indian Institute of Science, Bangalore and did his postdoctoral work at Imperial College, London and MIT before joining Penn State where he is a Professor. Prof. DebRoy’s work includes four edited books and 280 papers on computational materials processing, particularly in the application of numerical transport phenomena and optimization in welding. His papers have been cited over 3900 times in the literature.
Work of his many graduate students (21 PhDs) have been recognized by prestigious awards from American Welding Society (AWS), ASM International, American Iron and Steel Society, The International Institute of Welding (IIW), The American Vacuum Society, The University of Graz and The Pennsylvania State University. Professor DebRoy is an Honorary Member and Fellow of AWS and a Fellow of ASM International. His awards include The Yoshiaki Arata Award of IIW, Kenneth Easterling Best Paper Award of the University of Graz and IIW, The 57th Comfort A. Adams Lecture Award of AWS, and the Faculty Scholar Medal of Penn State.
He has given 14 keynote/plenary lectures in international conferences and numerous invited lectures in many prestigious institutions in Australia, Austria, Canada, China, Egypt, India, Japan, Sweden, Taiwan, Ukraine and USA. He is a Founding Editor of “Science and Technology of Welding and Joining,” and serves as a Principal Reviewer of Welding Journaland as the Chair of the Research and Development Committee of AWS.
We seek to quantitatively understand heat transfer, fluid flow and mass transfer during materials processing, particularly welding, chemical vapor deposition and metals processing. Much of our work involves numerical calculations of temperatures, velocities and concentrations using computers. The computed results provide detailed insight about the process and reveal how the composition and structure of the processed materials evolve. Our work focuses on overcoming two major problems of the current generation of models. First, the model predictions do not always agree with the experimental results because some process parameters or materials properties cannot be accurately prescribed. Second, and more important, these unidirectional models cannot determine multiple sets of process variables that can lead to a particular materials or process attribute. Our work shows that the computational convective heat and mass transfer models when combined with a genetic algorithm can overcome the aforementioned difficulties. The reliability of the models can be significantly improved by optimizing the values of the uncertain input parameters from a limited volume of experimental data. Furthermore, the procedure can calculate multiple sets of process variables, each leading to the same target materials or process attributes by conducting a global search within a phenomenological framework of the equations of conservation of mass, momentum and energy. This computational procedure was applied to gas tungsten arc welding of several alloys to calculate various sets of welding variables to achieve a specified weld geometry. Each set of welding parameters resulted in a specified geometry showing the effectiveness of the computational procedure.
Long-Qing Chen is Distinguished Professor of Materials Science and Engineering and Professor of Engineering Science and Mechanics at the Pennsylvania State University. He is a short-term visiting Professor of Materials Science and Engineering at Tsinghua University under the short-term 1000-Scholar program, a guest Professor of Materials Science and Engineering at Zhejiang University, and a guest Professor of Physics at the Beijing University of Science and Technology in China. He received his B.S. degree in Materials Science and Engineering from Zhejiang University in China in 1982. After spending one year as an assistant instructor at Zhejiang University, he came to the United States in 1983 and received his M.S. degree in Materials Science and Engineering from the State University of New York at Stony Brook in 1985 and a Ph.D. degree in Materials Science and Engineering from the Massachusetts Institute of Technology (MIT) in 1990. After a two-year post-doc appointment with Professor Armen G. Khachaturyanat Rutgers University, he joined the faculty at Penn State as an Assistant Professor of Materials Science and Engineering in 1992. He was promoted to Associated Professor in 1998 and Professor in 2002. Professor Chen teaches undergraduate thermodynamics of materials and graduate kinetics of materials processes and also co-teaches one graduate course and one undergraduate course in computational materials science in the department. Professor Chen's main research interest is developing multiscale computational models for predicting microstructure evolution in materials using a combination of atomistic/first-principles calculations and phase-field methods. In particular, he is interested in microstructure evolution during phase transformations, grain growth, Ostwald ripening, ferroelectric and multiferroic domain switching, and coupled ionic/electronic transport in electrochemical systems. His research group collaborates actively with numerous experimental groups, applied mathematicians, and other fellow computational materials scientists and physicists as well as with more than a dozen companies and national labs. Professor Chen has published over 350 authored or co-authored papers (H-index = 51, Number of Citations >10,000), 1 patent licensed by Intel, and co-edited 3 books in the area of computational materials science of microstructures and properties. He has given more than 200 invited talks including 6 at the Gordon Research Conferences. Professor Chen's current and former graduate students have received more than 40 awards including Materials Research Society Graduate Student Gold and Silver Medal Awards, American Ceramic Society Graduate Excellence in Materials Science Awards, Acta Materialia best student paper award, Penn State Materials Research Institute best Ph.D. thesis research award, TMS Young Leader Award, etc. Professor Chen received numerous awards for his work including:
Dr. Chen’s main research interest is in the fundamental understanding of the thermodynamics and kinetics of phase transformations and mesoscale microstructure evolution in bulk solid and thin films using computer simulations. Essentially all engineering materials contain certain types of microstructures, and our success of designing new materials is largely dependent on our ability to control them. Microstructure is a general term that refers to a spatial distribution of structural features that can be phases of different compositions and/or crystal structures, or grains of different orientations, or domains of different structural variants, or domains of different electrical or magnetic polarization, as well as structural defects such as dislocations. It is the size, shape, and spatial arrangement of the local structural features that determine the physical properties of a material such as mechanical, electrical, magnetic and optical properties. For the last decade, Dr. Chen’s group at Penn State is particularly active in developing phase-field models for microstructure evolution during various materials processes including grain growth, coherent precipitation, ferroelectric domain formation, particle coarsening, domain structure evolution in thin films, phase transformation in the presence of structural defects, and effect of stress on microstructure evolution. Current research focus is on the effect of stress/strain on ferroelectric phase transitions and domain structure evolution in ferroelectric and multiferroic thin films, domain structures in ferromagnetic shape memory alloys, electrode microstructure evolution in solid oxide fuel cells and batteries, precipitate microstructure evolution in Al-, Mg-, Ti- and Ni-alloys, strain-dominated morphological evolution, effect of defects such as dislocations on microstructure evolution. Dr. Chen’s group collaborates extensively with experimentalists and with industry.
Alloy development for aerospace and automobile iapplications
Ferroelectric and ferromagnetic thin films for memory, capacitor and electromechanical system applications
Solid oxide fuel cells and batteries
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