About this Abstract |
Meeting |
MS&T21: Materials Science & Technology
|
Symposium
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High Entropy Materials: Concentrated Solid Solutions, Intermetallics, Ceramics, Functional Materials and Beyond II
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Presentation Title |
Atomic Transport by Point Defects and Clusters in Concentrated Alloys |
Author(s) |
Osetsky Yury, Laurent Béland, Alexander Barashev, Yanwen Zhang |
On-Site Speaker (Planned) |
Osetsky Yury |
Abstract Scope |
Fascinating properties of many concentrated solid-solution alloys can be attributed to atomic-level diffusion and transport and the controlling mechanisms are complicated and depend very much on the alloy’s composition. Using microsecond-scale molecular dynamics, meso-scale kinetic Monte Carlo (kMC) and theory we have revealed the governing role of percolation effects and composition dependent defect formation and migration energies. An increase of concentration of faster species may decrease the overall atomic diffusion. Consequently, the composition dependence of diffusivity has a minimum near the corresponding mechanism percolation threshold and, we argue, may lead to the sluggish diffusion effect. Examples when additional element dramatically affects alloy diffusivity are given for fcc Ni-Fe-Cr system. A method for preselecting materials with potentially desired properties based on ab-initio informed kMC approach is suggested.This work was supported as part of the Energy Dissipation to Defect Evolution, an Energy Frontier Research Center funded by the US DOE/BES. |