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Advanced microstructural analysis of environmental degradation using site-specific transmission electron microscopy and atom-probe tomography


EMSL Project ID
46404

Abstract

Environmental degradation of Ni-based alloys continues to be a major problem in high-temperature water environments such as those found in nuclear reactors and steam generators. Despite several decades of research, there is no definitive answer as to the exact mechanisms by which these phenomena occur. Recently we have shown that site-specific microstructural analyses can be performed on corroded and oxidized surfaces, grain boundaries and crack tips with transmission electron microscopy and atom-probe tomography. We have developed novel focused-ion beam sample preparation techniques that enable highly-site-specific specimens (target volume ~100×100x100 nm3) to be prepared reliably for both analytical techniques. Here we propose to use these newly developed FIB, TEM and APT techniques to study the environmental degradation of both commercial alloys and model high-purity binary alloys exposed to high-temperature water environments. These studies will result in new microstructural insights into the mechanistic origins and behavior of environmental degradation and stress-corrosion cracking of materials critical to both current and next-generation nuclear reactor components. We will also continue to develop directly correlated TEM/APT studies and new FIB-based sample preparation methods within this proposal.

Project Details

Project type
Exploratory Research
Start Date
2012-01-11
End Date
2013-02-12
Status
Closed

Team

Principal Investigator

Daniel Schreiber
Institution
Pacific Northwest National Laboratory

Team Members

Matthew Olszta
Institution
Pacific Northwest National Laboratory

Larry Thomas
Institution
Pacific Northwest National Laboratory

Bruce Arey
Institution
Pacific Northwest National Laboratory