Monday, May 2nd, 2016 
Presentation Time: 11:00am 
Venue: Cymer Conference Center (Room 248) 
Structural Materials Engineering (SME) at UC San Diego

Dr. Arun Devaraj

Physical and Computational Sciences Directorate 
Pacific Northwest National Laboratory

Abstract:

Understanding the structure-property relationships is crucial for developing new materials with improved performance criteria for a variety of engineering applications. This has resulted in a growing need for improved material characterization methods to better understand structure-property relationships. This need is leading to development of new microstructural characterization methods and existing microscopy methods are entering new frontiers on a continuous basis. In this talk, a few specific examples will be presented for such approaches of decoding structure-property relationships of critical engineering materials using advanced characterization methods such as atom probe tomography (APT) and electron microscopy for three different inter-related research areas of energy storage, energy conversion and achieving energy efficiency for transportation. These will include examples of high performance energy storage materials, nanocomposite soft magnetic materials and advanced lightweight vehicle structural materials. Advanced energy materials, specifically high voltage and high capacity electrode materials for Li and Na-ion batteries, are of significant interest to the U.S. Department of Energy (DOE). To develop new batteries with improved performance, it is very important to correlate the electrochemical performance of battery materials with their nanostructure, which in turn can be influenced by the synthesis methods and by electrochemical cycling. Results of a multimodal chemical imaging approach using APT and scanning transmission electron microscopy (STEM)–energy-dispersive x-ray spectroscopy that provides new insights on capacity decay mechanisms will be presented [1]. The second example is nanocomposite soft magnetic materials which exhibit high magnetization and low coercivity for applications in power electronics, motors, and sensors. Results of linking local composition measurements of annealed nanocomposites from APT with observed magnetic properties of the material structure will be presented [2]. In the field of advanced lightweight vehicle structural materials, which also are of significant interest to DOE, an example of a new low cost nanostructured beta titanium alloy (Ti-1Al-8V-5Fe) will be presented, where multiscale characterization by scanning electron microscopy (SEM), TEM and APT helped correlate excellent tensile properties with the unique hierarchical nanostructure of the alloy [3]. Together these examples will highlight the role of advanced microstructural characterization in enhancing design of new materials for many different critical engineering applications. 
[1] A. Devaraj et al. Nature Communications, 6(8014), 2015 
[2] 2015V. DeGeorge et. al. IEEE Transactions on Magnetics, 51(6), 2015 (Featured cover) 
[3] A. Devaraj et al. Nature Communications, 7(11176), 2016

Biography:

Dr. Arun Devaraj is a senior research scientist in the Physical and Computational Sciences Directorate of Pacific Northwest National Laboratory. He received his Ph.D. in Material Science and Engineering from the University of North Texas in 2011. Before his graduate studies he worked as a process R&D engineer at an integrated steel plant, Essar Steel Ltd., Surat, India. He completed his undergraduate degree in Metallurgical Engineering at Malaviya National Institute of Technology, Jaipur, India. His research interest is in understanding microstructure-property relationships in a variety of materials including automotive structural materials, magnetic materials, energy materials, nuclear materials, and natural biomaterials using APT, in addition to correlating with SEM, FIB, TEM, x-ray spectroscopy, and x-ray diffraction at various DOE synchrotron facilities. Dr. Devaraj has more than 40 publications and has been the lead organizer of APT focus topic sessions at American Vacuum Society national meetings and serving as leader in the Microscopy Society of America Atom Probe Focused Interest Group.