NSUF 18-1253: Understanding the role of grain boundary character in segregation behavior of solute elements in neutron irradiated 304 SS using Atom Probe Tomography.
This project represents a critical step toward understanding quantitative relationship between microchemistry and strength of individual grain boundary (GB) for austenitic stainless steel (SS) samples. Upon irradiation of 304 SS, Radiation Induced Segregation (RIS) at GBs results in changes in the local composition which has direct implications on the corrosion resistance ability of SS. Thus, understanding of grain boundary chemistry is instrumental for predictability of mechanical properties of materials in the long term and mitigation routes for Irradiation Assisted Stress Corrosion Cracking (IASCC).
The suggested anisotropy in segregation behavior could be attributed to different energies of grain boundaries. In an effort to develop a full mechanistic understanding of RIS/RID, a systematic approach combining orientation imaging, site-specific specimen preparation and three-dimensional atomic-scale analysis has been proposed to characterize the behavior of solute elements at grain boundaries during irradiation. This methodology is currently aimed for 304SS sample irradiated at 3 dpa at 400°C. Systematic differences in segregation behavior is expected as function of grain boundary character (Sigma1, Sigma3, large angle grain boundary, and low angle grain boundary) and irradiation condition. Knowledge pertaining to segregation/depletion behavior for different grain boundary character would then be correlated to mechanical properties of materials (small scale tensile mechanical testing at INL).
Additional Info
| Field | Value |
|---|---|
| Abstract | This project represents a critical step toward understanding quantitative relationship between microchemistry and strength of individual grain boundary (GB) for austenitic stainless steel (SS) samples. Upon irradiation of 304 SS, Radiation Induced Segregation (RIS) at GBs results in changes in the local composition which has direct implications on the corrosion resistance ability of SS. Thus, understanding of grain boundary chemistry is instrumental for predictability of mechanical properties of materials in the long term and mitigation routes for Irradiation Assisted Stress Corrosion Cracking (IASCC). The suggested anisotropy in segregation behavior could be attributed to different energies of grain boundaries. In an effort to develop a full mechanistic understanding of RIS/RID, a systematic approach combining orientation imaging, site-specific specimen preparation and three-dimensional atomic-scale analysis has been proposed to characterize the behavior of solute elements at grain boundaries during irradiation. This methodology is currently aimed for 304SS sample irradiated at 3 dpa at 400°C. Systematic differences in segregation behavior is expected as function of grain boundary character (Sigma1, Sigma3, large angle grain boundary, and low angle grain boundary) and irradiation condition. Knowledge pertaining to segregation/depletion behavior for different grain boundary character would then be correlated to mechanical properties of materials (small scale tensile mechanical testing at INL). |
| Award Announced Date | 2018-02-01T14:18:16.21 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Yaqiao Wu |
| Irradiation Facility | None |
| PI | Mukesh Bachhav |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 1253 |