Processing and Characterization of Nanocrystalline Materials with Interesting Physical Properties

THE MORK FAMILY DEPARTMENT OF CHEMICAL ENGINEERING AND MATERIALS SCIENCEPRESENTS A SEMINAR
byAmiya K. MukherjeeDepartment of Chemical Engineering & Materials Science
University of California, DavisNanocrystalline materials have been produced by severe plastic deformation, electro-deposition, magnetron sputtering, crystallization from bulk metallic glass, ball milling and powders produced from inert gas condensation. The consolidation of the powder particles in some of these processing routes was achieved by electrical field assisted sintering with capability of superimposing 2 GPa gas pressure. The nanocrystalline metallic materials demonstrated both high strain-rate superplasticity and low-temperature superplasticity with important differences in the mechanistic details from their microcrystalline counterparts. The nanomaterials derived from crystallization of bulk metallic glass demonstrated extreme strength and at elevated temperatures showed superplasticity-like ductility. A three-phase alumina based nanoceramic composite demonstrated superplasticity at a lower temperature and at a higher strain rate. An alumina-carbon nanotube-niobium nanocomposite has a fracture toughness that is five times higher than that of pure alumina and an electrical conductivity that is thirteen orders of magnitude greater than that of pure nanocrystalline alumina. It also has excellent potential for use as a thermoelectric material. An alumina-spinel nanocomposite demonstrated optical transparency in the mid infrared range. A silicon carbide/silicon nitride nanocomposite produced by pyrolysis of liquid polymer precursor has produced one of the lowest creep rates in ceramics at a referred temperature of 1400° C. These structural and functional properties will be discussed in the context of microstructural investigations and recent results from molecular dynamics simulations. This research is supported by NSF, ARO, and ONR.Friday, April 21, 2006, 2:45-3:30 PM
(Refreshments will be served at 2:30 PM)
Location: VHE 217
**ALL FIRST YEAR MATERIALS SCIENCE MAJORS ARE REQUIRED TO ATTEND**

Location: Vivian Hall of Engineering (VHE) - 217

Audiences: Everyone Is Invited

Contact: Petra Pearce