About this Abstract |
Meeting |
MS&T22: Materials Science & Technology
|
Symposium
|
Tackling Structural Materials Challenges for Advanced Nuclear Reactors
|
Presentation Title |
Imaging Local Vacancy Supersaturation in Metals After Corrosion in Molten Salt |
Author(s) |
Yang Yang, Weiyue Zhou, Sheng Yin, Qin Yu, Robert Ritchie, Mark Asta, Ju Li, Michael Short, Andrew Minor |
On-Site Speaker (Planned) |
Yang Yang |
Abstract Scope |
Localized corrosion is a critical damage initiation step that can lead to early failure and unforeseen disasters in engineering systems. The progression of localized corrosion is often accompanied by the evolution of porosities in materials, creating internal mass-flow pathways which facilitate the ingression of the external environment into the interior of the material. Here, we discovered an extremely localized form of corrosion, which we call one-dimensional (1D) wormhole corrosion, is responsible for the fast penetration of salt in Ni-20Cr. Combining four-dimensional scanning transmission electron microscopy (4D-STEM) and density functional theory (DFT) simulation, we further developed a vacancy mapping method with nanometer spatial resolution. Using our technique, we identified that the diffusion-induced grain boundary migration (DIGM) zone is the precursor of these 1D wormholes, and it possesses a vacancy fraction up to 100 times greater than that of metals close to their equilibrium melting points. |