DBR Distinguished Speaker Series 2014-2015
"Harder, Cheaper, Greener: The Design and Deployment of Alloy Coatings with Stabilized Nanocrystalline Structures"
When the grain size of a metal is refined to a scale on the order of just a few nanometers, its strength, hardness, wear resistance, and other properties improve in dramatic ways. There is therefore significant interest in designing and deploying such nanocrystalline alloys for structural applications. However, refining the grain structure is a struggle against equilibrium, and nanocrystalline materials are often quite unstable; the grains grow given time even at room temperature, and the associated property benefits decline over time in service. In this talk, our efforts to design a stable family of nanocrystalline alloys will be described. We rely on selective alloying as a method to lower the energy of grain boundaries, bringing the nanocrystalline structure closer to equilibrium. Using analytical thermodynamic mixing calculations and Monte Carlo simulations, we identify desirable alloying elements for a given base metal, and assess the relative stability of nanocrystalline structures against grain growth. We then transition these modeling principles to the laboratory, produce materials, and experimentally validate the modeling results. Finally, the talk will review the connection between theory, experiment, and engineering application, and describe a suite of commercial products based on this research.
Christopher A. Schuh is the Department Head and the Danae and Vasilis Salapatas Professor of Metallurgy in the Department of Materials Science and Engineering at MIT. He joined MIT in 2002, having received a B.S. degree at the University of Illinois at Urbana-Champaign, and a Ph.D. at Northwestern University, both in the field of Materials Science and Engineering. Prof. Schuh also held the Ernest O. Lawrence postdoctoral fellowship at Lawrence Livermore National Laboratory. Prof. Schuh’s research is focused on structural metallurgy, and seeks to control disorder in metallic microstructures for the purpose of optimizing mechanical properties. Prof. Schuh has published more than 160 papers in scientific journals, and his research has received international attention through various awards, including the Robert Lansing Hardy Medal of the Metals, Minerals, and Materials Society. Prof. Schuh co-founded Xtalic Corporation, a technology spin-out company that has commercialized a new process for dynamically controlling the nanostructure in electrodeposited metals, with applications ranging from automotive and machine components to electronics. In 2011, Prof. Schuh was named a MacVicar Fellow of MIT, recognizing his contributions to engineering education.