Abstract
This work presents a detailed analysis of the diffusion fluxes near and at grain boundaries of irradiated Fe-Cr-Ni alloys, induced by preferential atom-vacancy and atom-interstitial coupling. The diffusion flux equations were based on the Perks model formulated through the linear theory of the thermodynamics of irreversible processes. The preferential atom-vacancy coupling was described by the mobility model, whereas the preferential atom-interstitial coupling was described by the interstitial binding model. The composition dependence of the thermodynamic factor was modeled using the CALPHAD approach. The calculated fluxes up to 10 dpa suggested the dominant diffusion mechanism for chromium and iron is via vacancy, while that for nickel can swing from the vacancy to the interstitial dominant mechanism. The diffusion flux in the vicinity of a grain boundary was found to be greatly modified by the segregation induced by irradiation, leading to the oscillatory behavior of alloy compositions in this region.
| Original language | English |
|---|---|
| Pages (from-to) | 35-53 |
| Number of pages | 19 |
| Journal | Journal of Nuclear Materials |
| Volume | 473 |
| DOIs | |
| State | Published - May 1 2016 |
Funding
This research was sponsored by the US Department of Energy, Office of Nuclear Energy , Light Water Reactor Sustainability Program, under Contract DE-AC05-00OR22725 with University of Tennessee – Battelle, LLC . Discussions with Prof. Murch on the applicability of Manning's relationship in this study are also appreciated.