ChEMS Seminar: In Situ Materials Science - Probing Microstructural Evolution of Metallic Materials in Real Time

Abstract: The field of materials science and engineering (MSE) is based on the fundamental principle that microstructure controls properties. Traditionally, the study of material structure has been limited by sectioning and postmortem observations. This approach is often inaccurate or inadequate for solving many fundamental problems. It is also often laborious and time consuming. Advances in experimental methods, analytical techniques and computational approaches have now enabled the development of in situ techniques that allow us to probe the behavior of materials in real time. The study of microstructures under an external stimulus (e.g., stress, temperature, environment) as a function of time is particularly exciting. Examples include an understanding of time-dependent deformation structures, phase transformations, compositional evolution, magnetic domains, etc. X-ray synchrotron micro and nano-tomography provides a wonderful means of characterization damage in materials non-destructively. In this talk, I will describe experiments and simulations that address the critical link between microstructure and deformation behavior of metallic materials, by using a three-dimensional (3-D) virtual microstructure obtained by X-ray synchrotron tomography. The approach involves capturing the microstructure by novel and sophisticated in situ testing in an X-ray synchrotron, followed by X-ray tomography and image analysis, and 3-D reconstruction of the microstructure. Case studies on fundamental precipitation evolution and deformation phenomena in high-performance aluminum alloys under cyclic loading and in a corrosive environment will be presented and discussed. New opportunities for X-ray microtomography, including lab-scale tomography and the next generation of X-ray synchrotron tomography will be highlighted.

Bio: Nikhilesh Chawla is director for the Center for 4-D Materials Science and is the Fulton Professor of Materials Science and Engineering (MSE) at Arizona State University. He is also a professor of mechanical engineering. Chawla received his doctorate in materials science and engineering from the University of Michigan in 1997.  He served as acting chair of the MSE program at ASU in 2010. Prior to joining ASU in 2000, he was a postdoctoral fellow jointly at Ford Motor Company and the University of Michigan, and a senior development engineer at Hoeganaes Corporation. 

Chawla’s research interests encompass the deformation behavior of advanced materials at bulk and small-length scales, including 4-D materials science, environmentally benign metallic alloys, composite materials and nanolaminates. He has co-authored close to 225 refereed journal publications (Web of Science h-index of 37; Google Scholar h-index of 47) and close to 450 presentations in these areas. He is the author of the textbook Metal Matrix Composites (co-authored with K.K. Chawla), published by Springer. The 2^nd edition of this book was published in 2013.

Chawla is a fellow of ASM International and past member of The Minerals, Metals, and Materials Society (TMS) Board of Directors. He’s the recipient of the New Mexico Tech Distinguished Alumnus Award for 2016. In addition, he received the 2016 Structural Materials Division Distinguished Scientist/Engineering Award, as well as the 2016 Functional Materials Division Distinguished Scientist/Engineering Award, both from TMS; 2013 Brimacombe Medalist Award from TMS; 2011 Distinguished Lectureship given by Tsinghua University, China; 2004 Bradley Stoughton Award for Young Teachers, given by ASM International; and the 2006 TMS Young Leaders Tutorial Lecture. He’s also won the National Science Foundation Early Career Development Award and the Office of Naval Research Young Investigator Award.

Chawla is editor of Materials Science and Engineering A published by Elsevier (2015 Impact Factor of 2.6). He also serves on the editorial boards of Advanced Engineering Materials, Materials Characterization, and Materials Chemistry and Physics. He has served or is serving on several external advisory boards, including that of the Naval Research Laboratory, the Advanced Photon Source at Argonne National Laboratory, and New Mexico Tech. His work has been featured on the show Modern Marvels on the History Channel, R&D News, Fox News and in the Arizona Republic. He serves on ASU President Michael Crow’s Academic Council, which provides input to the president on academic, structural and strategic matters.

Host: Xiaoqing Pan