NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Evolution of Local Microstructures: Spatial Instabilities of Coarsening ClustersThis work examines the diffusional growth of discrete phase particles dispersed within a matrix. Engineering materials are often microstructurally heterogeneous, and the details of the microstructure determine how well that material performs in a given application. Critical to the development of designing multiphase microstructures with long-term stability is the process of Ostwald ripening. Ripening, or phase coarsening, is diffusion-limited and arises in polydisperse multiphase materials. Growth and dissolution occur because fluxes of solute, driven by chemical potential gradients at the interfaces of the dispersed phase material, depend on particle size. Competitive kinetics of these processes dictates that larger particles grow at the expense of smaller ones, overall leading to an increase of the average particle size. The classical treatment of phase coarsening was done by Todes, Lifshitz, and Slyozov, (TLS) in the limit of zero volume fraction, V(sub V)=0 of the dispersed phase. Since the publication of TLS theory, there have been numerous investigations, many of which sought to describe the kinetic scaling behavior over a range of volume fractions. Some studies in the literature report that the relative increase in coarsening rate at low (but not zero) volume fractions compared to that predicted by TLS is proportional to V(exp 1/2)(sub v) whereas others suggest V(exp 1/3)(sub v).This issue has been addressed recently by simulation studies at low volume fractions in three dimensions by members of the Rensselaer/MSFC team.
Document ID
20010057250
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Glicksman, Martin E.
(Rensselaer Polytechnic Inst. Troy, NY United States)
Frazier, Donald O.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Rogers, Jan R.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Witherow, William K.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Downey, J. Patton
(NASA Marshall Space Flight Center Huntsville, AL United States)
Date Acquired
August 20, 2013
Publication Date
March 1, 2001
Publication Information
Publication: Microgravity Materials Science Conference 2000
Volume: 1
Subject Category
Chemistry And Materials (General)
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Document Inquiry

Available Downloads

There are no available downloads for this record.
No Preview Available