The role of boundary variability in polycrystalline grain-boundary diffusion
Abstract
We investigate the impact of grain-boundary variability on mass transport in a polycrystal. More specifically, we perform both numerical and analytical studies of steady-state diffusion in prototypical microstructures in which there is either a discrete spectrum of grain-boundary activation energies or else a complex distribution of grain-boundary character, and hence a continuous spectrum of boundary activation energies. An effective diffusivity is calculated for these structures using simplified multi-state models and, for the case of a continuous spectrum, employing experimentally obtained grain-boundary energy data. We identify different diffusive regimes for these cases and quantify deviations from Arrhenius behavior using effective medium theory. Finally, we examine the diffusion kinetics of a simplified model of an interfacial layering (i.e., complexion) transition.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 28, 2015
- Source ID
- 10.1063/1.4906778
Entities
People
- Helen M. Chan
- J. M. Rickman
- M. M. Moghadam
- M. P. Harmer
Organizations
- Lehigh University
- Office of Naval Research