How Grain Boundary Segregation Enables 3D Printing of Bulk Nanostructured Metals
Dr. Christopher A. Schuh
Massachusetts Institute of Technology
ABSTRACT: 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 even at room temperature, and the associated property benefits decline over time in service. In this talk, our efforts to design stable nano-crystalline alloys will be described. We rely on selective alloying as a method to lower the energy of grain boundaries, which can bring a nanocrystalline structure closer to equilibrium. This talk will highlight the path from theory, to proof-of-concept laboratory demonstration, to scale-up and commercialization of such alloys. Beginning from early successes with nanocrystalline alloy coatings, the talk will build to address current opportunities in bulk net-shape products and additive manufacturing.
BIOGRAPHY: 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. Schuh's academic training in Materials Science and Engineering focused on metals, including the processing, microstructure, and mechanics. He earned his B.S. degree from the University of Illinois at Urbana-Champaign in 1997, and his Ph.D. from Northwestern University in 2001. He held the Ernest O. Lawrence postdoctoral fellowship at Lawrence Livermore National Laboratory in 2001 before joining the faculty at MIT in 2002. Prof. Schuh's research is focused on structural metallurgy, and seeks to control disorder in metallic microstructures for the purpose of optimizing mechanical properties; much of his work is on the design and control of grain boundary structure and chemistry. Prof. Schuh has published more than 250 papers and dozens of patents and received a variety of awards acknowledging his research accomplishments. Prof. Schuh has co-founded a number of metallurgical companies, which have commercialized products ranging from high-performance electronic coatings to structural metal components, to 3D metal printers. Prof. Schuh also currently serves as the Coordinating Editor of the Acta Materialia family of journals. He has been named a MacVicar Fellow of MIT, acknowledging his contributions to engineering education, and is an elected Fellow of the ASM and TMS.