Colloquium: David Dunand, Novel Architectures in Metallic Foams: from Folded Origami to Twinning Struts

Abstract

Two methods are presented to create porous metallic structures with novel architectures. First, an additive method - direct printing - is used to create flat TiH2 powder lattices; these lattices are rolled into scrolls or folded into origami shapes and then reduced to Ti by vacuum sintering. The compressive properties of the scrolls, which could be used as bone implants, are presented and discussed. Second, a magnetic shape-memory alloy, Ni-Mn-Ga, is made porous by a subtractive method - removal of space-holder after casting. Porosity reduces incompatibility between grains, thus enabling magnetically-induced twinning that to date was only achievable in single crystals. The polycrystalline foams exhibit reversible magnetic field induced strains as high as 8%, which are repeatable over millions of cycles, and thus attractive for miniaturized actuators.

Bio

David Dunand received his Ph.D. from Massachusetts Institute of Technology (MIT) in 1991 and his BS/MS degree at the Swiss Federal Institute of Technology (ETH, Zurich) in materials science in 1986. After serving on the MIT faculty from 1991 to 1997, he joined Northwestern University (NU) where he is the James and Margie Krebs Professor of Materials Science and Engineering. He is the founding co-director of the Initiative for Sustainability and Energy at Northwestern, which since 2008 seeds new research, teaches interdisciplinary courses and creates outreach activities in the area of sustainable energy at NU.

Dunand holds eight patents, has published over 230 journal articles (including 31 in Materials Science and Engineering A), has co-edited three conference proceedings volumes, and is serving on several journal editorial boards. His research focuses on the processing, structure and mechanical properties of metallic alloys, composites and foams. Applications range from porous biomedical implants to light-weight foams for energy-efficient transportation, superconducting composites and temperature-resistant alloys for energy generation.

Dunand is a fellow of TMS (Minerals Metals and Materials Society) and ASM International, the recipient of the 2009 Distinguished Scientist/Engineering Award Structural Materials Division of TMS and a departmental Teacher of the Year at NU.