Abstract
Radiation-induced segregation (RIS) and subsequent depletion of chromium along grain boundaries has been shown to be an important factor in irradiation-assisted stress corrosion cracking in austenitic face-centered cubic (fcc)-based alloys used for nuclear energy systems. A full understanding of RIS requires examination of the effect of the grain boundary character on the segregation process. Understanding how specific grain boundary structures respond under irradiation would assist in developing or designing alloys that are more efficient at removing point defects, or reducing the overall rate of deleterious Cr segregation. This study shows that solute segregation is dependent not only on grain boundary misorientation, but also on the grain boundary plane, as highlighted by markedly different segregation behavior for the Σ3 incoherent and coherent grain boundaries. The link between RIS and atomistic modeling is also explored through molecular dynamic simulations of the interaction of vacancies at different grain boundary structures through defect energetics in a simple model system. A key insight from the coupled experimental RIS measurements and corresponding defect-grain boundary modeling is that grain boundary-vacancy formation energy may have a critical threshold value related to the major alloying elements' solute segregation.
| Original language | English |
|---|---|
| Pages (from-to) | 145-155 |
| Number of pages | 11 |
| Journal | Acta Materialia |
| Volume | 67 |
| DOIs | |
| State | Published - Apr 2014 |
Funding
M.L.T. and C.M.B. acknowledge funding from The US Nuclear Regulatory Commission under Grant NRC-38-10-928 for this work. X.M.B. acknowledges the support from the Energy Frontier Research Center (EFRC) Program at Idaho National Laboratory funded by the US Department of Energy, Office of Basic Energy Sciences (FWP 1356). This work was partially supported by the US Department of Energy, Office of Basic Energy Sciences. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the US Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000. Research supported by the Center for Nanophase Materials Sciences (CNMS), which is sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy.
Keywords
- Atomistic modeling
- Austenitic steel
- Grain boundaries
- Ion irradiation
- Radiation-induced segregation