MRS Bulletin

Technical Feature

Technical Feature

Visualizing the Behavior of Dislocations—Seeing is Believing

Ian M. Robertson, Paulo J. Ferreira, Gerhard Dehm, Robert Hull and Eric A. Stach


The spatial resolution of the transmission electron microscope makes it an ideal environment in which to continuously track the real-time response of a system to an external stimulus and to discover and quantify the rate-limiting fundamental microscopic processes and mechanisms governing the macroscopic properties. Advances in instrumentation, stage design, recording media, computational power, and image manipulation software are providing new opportunities for not only observing the microscopic mechanisms but also measuring concurrently the macroscopic response. In this article, the capability of this technique as applied to mechanical properties of materials is highlighted.

Ian M. Robertson is a Willett Professor of Engineering and head of the Department of Materials Science and Engineering at the University of Illinois at Urbana-Champaign (UIUC). He obtained his BSc degree in applied physics from Strathclyde University in Glasgow, Scotland, and his DPhil degree from University of Oxford, England, in 1982. Robertson then joined the Department of Metallurgy and Mining at the University of Illinois at Urbana-Champaign as a postdoctoral assistant. He became a member of the faculty of that department in 1984. Currently, Robertson also is an affiliate faculty member of the Department of Mechanical Science and Engineering at UIUC. Robertson's research interests include application of the transmission electron microscope as an experimental laboratory for understanding the fundamental processes and mechanisms that control the macroscopic response of materials exposed to extreme environments (temperature, strain rate, gaseous and liquid environments, and irradiation), and identifying the processes limiting hydrogen uptake and release in lightweight hydrogen storage materials.

Robertson can be reached at the Department of Materials Science and Engineering, University of Illinois, 1304 West Green Street, Urbana IL 61801, USA; and e-mail

Paulo J. Ferreira, Guest Editor for this issue of MRS Bulletin, is an assistant professor at the University of Texas at Austin. Ferreira earned his PhD degree in materials science and engineering from the University of Illinois. He completed his post-doctoral work in materials science and engineering at the Massachusetts Institute of Technology. Ferreira concentrates his scientific research on the study of the atomic structure and defect behavior of nanomaterials through in situ and high-resolution transmission electron microscopy techniques. He is part of the editorial board of review for Metallurgical and Materials Transactions. Ferreira also has acted as a special advisor to the Minister of Economics and Innovation, Portugal, on Government Strategy for Science & Technology. In addition, Ferreira is the author or co-author of more than 70 papers, conference proceedings, and book chapters. He is preparing a book entitled “Nanomaterials, Nanotechnologies and Design: An Introduction for Engineers and Architects” with coauthors D. Schodek (Harvard University) and M. Ashby (University of Cambridge, UK).

Ferreira can be reached at the University of Texas at Austin, Materials Science and Engineering Program, 1 University Station, MC 2200, Austin, TX 78712–0292, USA; tel. 512-471-3244, and e-mail

Gerhard Dehm is a professor and chair of the Department Materials Physics of the Montanuniversität Leoben in Austria, and director of the Erich Schmid Institute of Materials Science of the Austrian Academy of Sciences. He studied materials science at the University of Erlangen- Nuremberg and received his PhD degree from the University of Stuttgart/Max Planck Institute for Metals Research in 1995. Dehm was a visiting scientist at the Technion–Israel Institute of Technology in Haifa with a Feodor Lynen scholarship of the Alexander von Humboldt Foundation. Afterward, he was a senior scientist at the Max Planck Institute for Metals Research in Stuttgart. Dehm then moved to Austria in 2005. His field of research includes mechanical size-effects in thin films and nanostructured materials, interface related phenomena in metals and metal/ceramic systems, and in situ electron microscopy. Dehm has received several awards, including the Masing Memorial Award from the German Materials Society DGM, and the Award for Nanosciences of Styria.

Dehm can be reached by e-mail at gerhard.

Robert Hull is the Henry Burlage Professor and head of the Materials Science and Engineering Department at Rensselaer Polytechnic Institute (RPI). He received his PhD degree in materials science from Oxford University, and then spent 10 years at AT&T Bell Laboratories. Hull then joined the faculty of the Materials Department at the University of Virginia, where he served as director of an NSF MRSEC Center and of the University of Virginia Nanoscience Institute. Afterward, Hull moved to RPI. His recent research focuses upon the development of new techniques for nanoscale assembly, fabrication, and characterization using focused ion and electron beams, with particular emphases on in situ imaging methods, epitaxial semiconductor structures, and materials for nanoelectronics. He has published more than 200 journal and conference papers in these and related fields. Hull is a fellow of the American Physical Society, a member of the European Academy of Sciences, and has served as the president of the Materials Research Society.

Eric A. Stach, Guest Editor for this issue of MRS Bulletin, is an associate professor in the Department of Materials Engineering at Purdue University and scientific director of the Electron Microscopy Facility at the Birck Nanotechnology Center. He received his PhD degree in 1998 in materials science and engineering from the University of Virginia. Prior to joining Purdue, Stach was the in situ staff scientist (1998–2003) and a principal investigator (2003–2004) at the National Center for Electron Microscopy. He also is chief scientist and co-founder of Humming bird Scientific, LLC; a manufacturer of sample holders for electron and ion microscopy applications. Stach's research interests focus on the development and application of in situ electron microscopy techniques toward understanding crystal growth and deformation mechanisms.