Researchers across Lehigh University’s colleges and departments will soon be able to conduct experiments using a new, state-of-the-art plasma focused ion beam system, or FIB, together with the capability for in situ mechanical testing at various temperatures between minus 130 and 1000 degrees Celsius.
The National Science Foundation recently awarded Lehigh more than $1.2 million to purchase the new instrumentation. The award is part of the foundation’s Major Research Instrumentation program (MRI), which supports the development or acquisition of equipment that will advance science and engineering. In addition to the NSF award, Lehigh University also provided a significant proportion of cost-sharing to make the acquisition possible. One of the goals of such grants is to significantly impact research in a broad range of areas.
“We had 25 faculty members involved in this proposal, all of whom submitted projects requiring the FIB system, and many of them are associated with Lehigh’s Interdisciplinary Research Institutes,” says Masashi Watanabe, a professor of materials science and engineering and a major contributor on the proposal. “And they represent a range of disciplines, including materials science, mechanical engineering, chemical engineering, industrial engineering, bioengineering, physics, chemistry, and biology. There’s just such a high demand for a machine like this.”
“The FIB system is a micro-/nano-fabrication tool that is able to precision-machine samples in a rapid and efficient way, similar to woodworking, but at the micrometer or even nanometer level,” says lead researcher Helen Chan, New Jersey Zinc Professor of Materials Science and Engineering. “And the fixture that allows for in situ mechanical testing enables us to indent or pull or push on a material so we can simultaneously watch how the material fractures and deforms. Even more exciting, we can study the effect of temperature on the deformation process.”
One possible application is the study of microstructural elements that might not be obtainable in bulk form. For example, suppose there is a particular phase that occurs as fine, micron-sized dispersions within a matrix of another material. Bulk testing would only be able to measure the aggregate behavior of the dispersions and matrix. Using the FIB system, however, it would be possible to machine a micromechanical sample in a location such that only the volume of material within a single dispersion was tested.
Chan says the EBSD (electron backscattered diffraction) capability is exciting because when certain materials are subjected to a stress, a phase or orientation change can take place, and this is detectable by EBSD. “These changes are often highly localized, and hence difficult to observe in bulk samples,” she says. “With in situ mechanical testing with EBSD analysis, we can observe these changes as a function of the stress and correlate with changes in the properties.”
“The biomaterials and polymer materials are so-called soft matters, which are quite challenging to observe inside of materials due to the softness nature of materials,” says Watanabe. “One of the most effective approaches to fabricate or cut out such soft materials is cooling down to a liquid nitrogen temperature. The FIB system to be installed is equipped with a cryo-stage and cryo-manipulators, which allows for the sectioning of soft materials at micrometer scales. Using the FIB system at cryo-temperatures, it is possible to apply for cross-sectioning of soft samples with ions for internal observation within the FIB or to prepare an electron-transparent thin specimen for further detailed observations at nanometer scales in transmission electron microscopy (TEM).”
The university currently has a focused ion beam milling machine that works on germanium ions. The new FIB will work on xenon ions, says Chan, making it up to 10 times faster, which allows for more fabrication of micromechanical test samples. Right now, producing enough such samples to allow for statistically significant testing is a major limitation for researchers.
The new instrumentation also includes an ultra-high-speed electron camera for acquisition of EBSD patterns. which is particularly novel.
“It will allow us to see the orientation, meaning the crystal structure of a particular sample,” says Watanabe. “We’ll be targeting 2000 to 3000 patterns per second, which is incredibly fast. So during deformation, we’ll be able to see these crystal structure changes as they’re happening. This is very new. Nobody has done that.”
Such information will inform researchers on how cracks in structures initiate, says Chan. There may be “weak links” in the microstructure that could be alleviated by improved processing. “We would like to build into structures “crack stoppers” that make it more difficult for cracks to propagate,” she says. “The net result would be structures that exhibit higher toughness and longer lifetimes.”
The team, which also includes mechanical engineering and mechanics faculty members Natasha Vermaak and John Coulter (the Rossin College’s senior associate dean for research) and Loewy Professor of Materials Forming and Processing Wojciech Misiolek (chair of the Department of Materials Science and Engineering), expects the FIB system to be up and running by June. It will be located in the university’s new Health, Science, and Technology (HST) building. The facility also houses Lehigh’s world-class surface characterization and x-ray diffraction and scattering tools, as well as cutting-edge virtual and augmented reality capabilities.
Related Links:
- NSF Abstract (# 2215267): MRI: Acquisition of a Plasma Focused Ion Beam System for Dynamic In-situ Micro-Mechanical Testing…
- Rossin College Faculty Profile: Helen M. Chan
- Rossin College Faculty Profile: Masashi Watanabe
- Rossin College Faculty Profile: John P. Coulter
- Rossin College Faculty Profile: Natasha Vermaak
- Rossin College Faculty Profile: Wojciech Z. Misiolek
- Lehigh University: Health, Science and Technology building
- Lehigh University: Interdisciplinary Research Institutes
About Helen Chan
Helen Chan is the New Jersey Zinc Professor of Materials Science and Engineering in Lehigh University’s P.C. Rossin College of Engineering and Applied Science.
Her research interests include the application of reactive processing to fabricate unique ceramic/metal structures; the processing, properties, and advanced characterization of high-entropy alloys; the mechanical behavior of ceramic composites; and the role of interfacial chemistry in determining the elevated temperature mechanical behavior of ceramics. She has also been actively involved in research on the processing and microstructural development of lead based relaxor ferroelectrics for transducer/actuator applications.
Chan has authored more than 200 publications, given hundreds of talks and presentations, and holds five U.S. patents.
She is a Fellow of the American Ceramic Society (2005), has served as an associate editor for the Journal of the American Ceramic Society since 1999, and is a five-time recipient of the ACS Roland B. Snow Award.
Chan joined the Lehigh faculty 1986 and also spent time in the Mechanical Properties Group of the Ceramics Division during her early career. She served as chair of Lehigh’s Department of Materials Science and Engineering from 2006 to 2016. Lehigh has recognized Chan for excellence in research, teaching, and professional achievement through Hillman Faculty Award (2017), Eleanor and Joseph F. Libsch Research Award (2005), the Service Teaching Excellence Award (1991, 1992, and 2007), the Class of 1961 Professorship (1993), and the Alfred Noble Robinson Faculty Award (1990).
Chan was named the 1992 recipient of ASM International’s Bradley Stoughton Award for outstanding young faculty in the field of materials science and engineering. She served as editor of the Journal of Materials Science from 2004-2015. She chaired the 2008 Gordon Research Conference on Solid State Ceramics.
She received her B.Sc. and PhD from the Department of Materials Science & Technology at Imperial College (University of London).
About Masashi Watanabe
Masashi Watanabe is a professor of materials science and engineering in the P.C. Rossin College of Engineering and Applied Science at Lehigh University.
His research emphasizes materials characterization using various electron microscopy approaches involving analysis via X-rays and energy-loss electrons in analytical electron microscopes (AEMs) and atomic-resolution high angle annular dark-field (HAADF) imaging in scanning transmission electron microscopes (STEMs). He developed the zeta-factor method for quantitative X-ray analysis and implemented multivariate statistical analysis (MSA) for spectrum images of X-rays and energy-loss electrons.
Watanabe is affiliated with Lehigh’s Materials Characterization Facility as an associate director under the Institute for Functional Materials and Devices (I-FMD) and has served as an organizer and lecturer for the world-renowned Lehigh Microscopy School since 2001. He has been a lecturer for other microscopy schools, including the Arizona State University Winter School on High Resolution Electron Microscopy (since 2008) and the Nano Science Education Program in Osaka University in Japan (since 2015). He served as a president of the Microanalysis Society (2016-2018) and is a Fellow of the Microanalysis Society (2019) and the Microscopy Society of America (2020).
Watanabe has more than 250 research publications in scientific journals and conference proceedings, and has given more than 150 invited presentations and seminars at numerous conferences and institutions. He is the recipient of numerous awards, including the K.F.J. Heinrich Young Scientist Award from the Microbeam Analysis Society (2005), the Kazato Prize from the Kazato Research Foundation (2008), and the Seto Award (the Society Award) from the Japanese Society of Microscopy (2011).
