-------------------------------------------------------------------- COLLOQUIUM OF THE COMPUTATIONAL MATERIALS SCIENCE CENTER AND THE SCHOOL OF PHYSICS, ASTRONOMY, & COMPUTATIONAL SCIENCES (CSI 898-Sec 001) -------------------------------------------------------------------- Revealing the Hidden Structure in Supercooled Metallic Liquids Howard Sheng School of Physics, Astronomy & Computational Sciences, George Mason University, Fairfax, VA When metallic liquids are deeply supercooled without crystallization, they eventually form metallic glasses, which are considered as the next-generation engineering materials. Structural ordering plays an important role in the formation of metallic glasses from their liquid predecessors. While topological short-range ordering (SRO), i.e., atomic packing within the first two atomic shells in amorphous metals has been widely studied in the past, structural features of metallic glasses on the nanometer scale have not been clear. In this talk, I will first introduce computational methodologies to study the structure, formation and properties of metallic glasses. Several new features concerning the structural evolution of metallic liquids will be revealed. Our approach hinges on the development of high-accuracy interatomic potentials based on extensive first-principles calculations. Short-to-medium structural ordering and structural heterogeneity in supercooled liquids are investigated with molecular dynamics (MD) simulations and linked with experiment observations for critical comparison. I shall talk about new features concerning the medium-range structural ordering of supercooled liquids during the vitrification process. The relationships among structural ordering, relaxation dynamics and properties of metallic glasses will be discussed. Lastly I shall discuss several pitfalls in structural modeling of metallic glasses, especially the ones involving the "reverse" approach. November 12, 2012 4:30 pm Room 301, Research I, Fairfax Campus Refreshments will be served at 4:15 PM. ---------------------------------------------------------------------- Find the schedule at http://www.cmasc.gmu.edu/seminars.htm