Structures and Dynamics in Condensed Systems

Personnel

Project Leader(s):
Matthew Kramer

Principal Investigators:
Alan Goldman, Matthew Kramer, Mikhail Mendelev, Ralph Napolitano, Ryan Ott, Xueyu Song, Cai-Zhuang Wang,

Postdoctoral Research Associates:
Shaogang Hao

Overview

This project concentrates on developing quantitative, self-consistent structural descriptions of liquid and amorphous states in metallic systems. Our research moves beyond static structural descriptions towards a detailed thermodynamic understanding of liquid and amorphous states, consistent with structural models. Binary alloys are emphasized to more accurately describe local structure. Moreover, the capabilities of the Materials Preparation Center are utilized to synthesize high-purity alloys having precise composition control. Experimental methods, atomistic simulations, and fundamental theoretical predictions are integrated for the measurement of structure, chemistry, and macroscopic thermodynamic properties in selected liquid and amorphous Al- and Zr-based model systems.

This project utilizes DOE-supported x-ray and neutron sources to capture structural- and chemically-specific details about short- and medium-range order in disordered systems. In addition, targeted scattering data are used to support efforts to develop highly accurate inter-atomic potentials. Simulation approaches include ab initio, constrained reverse Monte Carlo, and classical molecular dynamics using both pair-wise and, more importantly, many-body inter-atomic potentials, including tight-binding and embedded-atom method approaches. A new "embedded-cluster" method for ab initio calculations is pursued to mitigate the artifacts created by periodic boundary conditions of conventional first-principles methods. Combined with experimental data, simulations ultimately allow us to predict—e.g., changes in temperature, strain, or composition—alterations in local and long-range atomic ordering, leading to different disordered structures or perhaps highly-correlated phase transformations.

Highlights

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Publications

2009
Wang S Y; Wang C Z; Zheng C X; Ho K M . 2009. Structure and dynamics of liquid Al1-xSix alloys by ab initio molecular dynamics simulations. Journal of Non-Crystalline Solids. 355:340-347. abstract
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Mendelev M I; Ott R T; Kramer M J; Sordelet D J . 2009. Determining strain in amorphous alloys: Uncertainties with analyzing structural changes during deformation. Journal of Applied Physics. 105:023509. abstract
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Qu W; Tan X; Vittayakorn N; Wirunchit S; Besser M F . 2009. High temperature phases in the 0.98PbZrO(3)-0.02Pb(Ni1/3Nb2/3)O-3 ceramic. Journal of Applied Physics. 105:014106. abstract
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Mendelev M I; Kramer M J; Ott R T; Sordelet D J . 2009. Molecular dynamics simulation of diffusion in supercooled Cu-Zr alloys. Philosophical Magazine. 89:109-126. abstract
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Warshavsky V B; Song X . 2009. Phase diagrams of binary alloys calculated from a density functional theory. Physical Review B. 79:014101. abstract
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2008
Mendelev M I; Ott R T; Heggen M; Feuerebacher M; Kramer M J; Sordelet D J . 2008. Deformation behavior of an amorphous Cu64.5Zr35.5 alloy: A combined computer simulation and experimental study. Journal of Applied Physics. 104:123532. abstract
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Ott R T; Heggen M; Feuerbacher M; Park E S; Kim D H; Kramer M J; Besser M F; Sordelet D J . 2008. Anelastic strain and structural anisotropy in homogeneously deformed Cu64.5Zr35.5 metallic glass. Acta Materialia. 56:5575-5583. abstract
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Zhou S H; Napolitano R E . 2008. Energetics of nonequilibrium solidification in Al-Sm. Physical Review B. 78:184111. abstract
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Zhou S H; Napolitano R E . 2008. Identification of the B33 martensite phase in Cu-Zr using first-principles and X-ray diffraction. Scripta Materialia. 59:1143-1146. abstract
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Wang S Y; Wang C Z; Li M Z; Huang L; Ott R T; Kramer M J; Sordelet D J; Ho K M . 2008. Short- and medium-range order in a Zr73Pt27 glass: Experimental and simulation studies. Physical Review B. 78:184204. abstract
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