skip to main content

Title: Glass Formation by a Nucleation and Growth Process as in a First-order Transition

There are two quite different views of metallic glasses. One is that a glass forms when an undercooled melt becomes kinetically frozen into a well of an energy landscape. This mechanism is quite univemore »rsal and in principle occurs for all melts if they can be cooled rapidly enough. Usually such glasses tolerate the same wide compositional variations of melts.In the other view the glass is an efficient high-density low-energy packing of atoms into an aperiodic isotropic structure. These glasses, which we dubbed q-glasses, are expected to be less tolerant of composition variations. Evidence of the existence of a q-glass in Al-Fe-Si is presented. The glass is the first phase to form from the melt on cooling, and it forms by a nucleation and growth process.A detailed study of the formation of this glass from melts over a wide range of compositions reveals that the glass behaves like a stoichiometric compound, with a concentration near 15 a/o Fe, 20a/o Si. There is an interface between the growing glass and the melt. When the melt differs from the concentration of the glass, we find partitioning at this interface and isotropic Mullins-Sekerka instabilities. With enough partitioning an icosahedral phase and/or complex intermetallic compounds, all with near-by compositions, form. Studies are underway to see if the glass and these other phases have similar local atomic packings.« less
Title: Glass Formation by a Nucleation and Growth Process as in a First-order Transition
Publication Date: 2005-03-02
OSTI Identifier: 1007907
DOE Contract Number: ACO2-06CH11357
Resource Type: Multimedia
Resource Relation: Conference: APS Colloquium Series, Advanced Photon Source (APS) at Argonne National Laboratory, Argonne, Illinois (United States), presented on March 02, 2005
Research Org: ANL (Argonne National Laboratory (ANL), Argonne, IL (United States))
Sponsoring Org: USDOE Office of Science (SC)
Country of Publication: United States
Language: English
Run Time: 0:32:03
System Entry Date: 2016-01-28