Diffusion of He Interstitials and He Clusters in α-Fe
The accumulation of He atoms in materials will significantly degrade the mechanical properties of materials; therefore, understanding the properties of He interstitials and their clusters in materials is of fundamental importance within a fusion reactor environment. The diffusion properties of single He interstitials and He clusters in the bulk and grain boundaries of α-Fe are being studied using molecular dynamics with a new Fe-He potential. It is found that the migration barrier for a single He interstitial in the bulk is very low, which is consistent with the result obtained using ab initio methods. Large He clusters can cause Fe self-interstitial atoms (SIA) to be formed, which can be trapped by the resulting vacancy, forming a He-vacancy complex. It is found that for He interstitials in grain boundaries (GBs), the He migration is one-dimensional in a Σ11 GB, while it is two-dimensional in a Σ3 GB at 600 K and three-dimensional at higher temperatures.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1023728
- Report Number(s):
- PNNL-SA-78785; AT6020100
- Country of Publication:
- United States
- Language:
- English
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