About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
|
| Symposium
|
Vacancy Engineering in Metals and Alloys
|
| Presentation Title |
Nanoscale vacancy mapping in metals by four-dimensional scanning transmission electron microscopy (4D-STEM) |
| Author(s) |
Yang Yang |
| On-Site Speaker (Planned) |
Yang Yang |
| Abstract Scope |
Vacancies are ubiquitous in materials and can become supersaturated under extreme conditions such as corrosion or irradiation. A detailed nanoscale mapping of vacancies is essential to reveal their interactions with other defects and the resulting effects on materials' properties. Here, integrating four-dimensional scanning transmission electron microscopy (4D-STEM), energy-dispersive X-ray spectroscopy (EDX), and density functional theory (DFT) simulations, we developed a nanometer-scale vacancy mapping method. We have applied this approach to study two systems. First, in Ni-20Cr exposed to molten salt corrosion, the method identified precursors of one-dimensional wormhole corrosion in the diffusion-induced grain boundary migration (DIGM) zones, with vacancy concentrations nearly 100 times higher than in metals near their melting points. Second, in-situ dealloying of Cu-Zn alloys further demonstrated the effectiveness of this method. This work highlights the critical role of nanoscale vacancy characterization in understanding material degradation under extreme environments. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Characterization, Environmental Effects, Nanotechnology |