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                                           BIOINFORMATICS COLLOQUIUM
					       College of Science
                                            George Mason University
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				 How do atoms pack themselves in amorphous metals?
					
						Howard Sheng, Ph.D.

	      			 		     Professor
					      George Mason University

Abstract:
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.