title: Fractal atomic-level percolation in metallic glasses.
abstract: Metallic glasses are metallic alloys that exhibit exotic material properties. They may have fractal structures at the atomic level, but a physical mechanism for their organization without ordering has not been identified. We demonstrated a crossover between fractal short-range (<2 atomic diameters) and homogeneous long-range structures using in situ x-ray diffraction, tomography, and molecular dynamics simulations. A specific class of fractal, the percolation cluster, explains the structural details for several metallic-glass compositions. We postulate that atoms percolate in the liquid phase and that the percolating cluster becomes rigid at the glass transition temperature.
authors.affiliation: Division of Engineering and Applied Sciences, California Institute of Technology, Pasadena, CA 91125, USA. dzchen@caltech.edu.
authors.forename: David Z
authors.initials: DZ
authors.lastname: Chen
authors.affiliation: Department of Geological Sciences, Stanford University, Stanford, CA 94305, USA.
authors.forename: Crystal Y
authors.initials: CY
authors.lastname: Shi
authors.affiliation: Materials and Process Simulation Center, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Qi
authors.initials: Q
authors.lastname: An
authors.affiliation: Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China. High Pressure Synergetic Consortium, Geophysical Laboratory, Carnegie Institute of Washington, Argonne, IL 60439, USA.
authors.forename: Qiaoshi
authors.initials: Q
authors.lastname: Zeng
authors.affiliation: Department of Geological Sciences, Stanford University, Stanford, CA 94305, USA. Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
authors.forename: Wendy L
authors.initials: WL
authors.lastname: Mao
authors.affiliation: Materials and Process Simulation Center, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: William A
authors.initials: WA
authors.lastname: Goddard
authors.affiliation: Division of Engineering and Applied Sciences, California Institute of Technology, Pasadena, CA 91125, USA. Kavli Nanoscience Institute, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Julia R
authors.initials: JR
authors.lastname: Greer