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Diffusion and interdiffusion in binary metallic melts

Kuhn, P. (1) and Horbach, Jürgen and Kargl, Florian and Meyer, Andreas and Voigtmann, Thomas (2014) Diffusion and interdiffusion in binary metallic melts. Physical Review B - Condensed Matter and Materials Physics, 90, 024309. American Physical Society. doi: 10.1103/PhysRevB.90.024309. ISSN 1098-0121.

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We discuss the dependence of self- and interdiffusion coefficients on temperature and composition for two prototypical binary metallic melts, Al-Ni and Zr-Ni, in molecular-dynamics (MD) computer simulations and the mode-coupling theory of the glass transition (MCT). Dynamical processes that are mainly entropic in origin slow down mass transport (as expressed through self diffusion) in the mixture as compared to the ideal-mixing contribution. Interdiffusion of chemical species is a competition of slow kinetic modes with a strong thermodynamic driving force that is caused by non-entropic interactions. The combination of both dynamic and thermodynamic effects causes qualitative differences in the concentration dependence of self-diffusion and interdiffusion coefficients. At high temperatures, the thermodynamic enhancement of interdiffusion prevails, while at low temperatures, kinetic effects dominate the concentration dependence, rationalized within MCT as the approach to its ideal-glass transition temperature $T_c$. The Darken equation relating self- and interdiffusion qualitatively reproduces the concentration-dependence in both Zr-Ni and Al-Ni, but quantitatively, the kinetic contributions to interdiffusion can be slower than the lower bound suggested by the Darken equation. As temperature is decreased, the agreement with Darken's equation improves, due to a strong coupling of all kinetic modes that is a generic feature predicted by MCT.

Item URL in elib:https://elib.dlr.de/90081/
Document Type:Article
Title:Diffusion and interdiffusion in binary metallic melts
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Horbach, JürgenUniversität DüsseldorfUNSPECIFIED
Kargl, Florianflorian.kargl (at) dlr.deUNSPECIFIED
Meyer, Andreasandreas.meyer (at) dlr.deUNSPECIFIED
Voigtmann, Thomasthomas.voigtmann (at) dlr.deUNSPECIFIED
Journal or Publication Title:Physical Review B - Condensed Matter and Materials Physics
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In ISI Web of Science:No
DOI :10.1103/PhysRevB.90.024309
Page Range:024309
Publisher:American Physical Society
Keywords:mode coupling theory, diffusion, interdiffusion, metallic melts, alloys, Zr-Ni, Al-Ni, molecular dynamics simulation, Darken equation
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Research under Space Conditions
DLR - Research area:Raumfahrt
DLR - Program:R FR - Research under Space Conditions
DLR - Research theme (Project):R - Vorhaben Materialwissenschaftliche Forschung (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Materials Physics in Space
Deposited By: Voigtmann, Dr.rer.nat. Thomas
Deposited On:04 Aug 2014 14:12
Last Modified:19 Oct 2021 09:57

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