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           COLLOQUIUM OF THE COMPUTATIONAL MATERIALS SCIENCE CENTER
                              College of Science
                       (CDS Department CSI 898-Sec 001)
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      How do atoms pack themselves in amorphous metals?

                        Howard Sheng 
  Dep. of Computational and Data Sciences, George Mason University

The metals that we are familiar with are crystalline materials 
with atoms arranged in orderly lattices. In recent years, a new 
type of metals - amorphous metals (also known as metallic glasses)-
 has been discovered and pushed onto the frontier of metals 
research. Owing to many outstanding properties, metallic glasses 
are projected as next generation engineering materials. However, 
as much as we recognize that the atomic-level structures of 
metallic glasses are distinctly different from crystalline 
materials, how exactly atoms pack themselves in metallic glasses 
is far from being well understood. In this talk, I will demonstrate 
that state-of-the-art computational methods, in combination with 
advanced experimental structural analysis techniques, can be used 
to unravel the details of atomic packing in amorphous metals. 
Special emphasis will be placed on spatial tessellation and 
analysis of atomic configurations obtained from computational 
approaches. A general picture will then be provided for binary 
metallic glasses: Local motifs of metallic glasses consist of 
topologically ordered atomic clusters (Kasper Polyhedra); these 
quasi-equivalent clusters join each other in an icosahedral-like 
fashion to form high-level super structures.  The new structural 
description of metallic glasses will help understand the formation, 
deformation mechanisms, as well as other important physical properties 
of metallic glasses.   
                        Monday , November 19, 2007
                                  4:30 pm
                     Room 301, Research I, Fairfax Campus

Refreshments will be served at 4:15 PM.
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Find the schedule at www.cmasc.gmu.edu/seminar/schedule.html
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