About this Abstract |
Meeting |
2024 TMS Annual Meeting & Exhibition
|
Symposium
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Advances in the State-of-the-Art of High Temperature Alloys
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Presentation Title |
Role of Diffusion-induced Grain Boundary Migration in the Oxidation Response of a Ni-30Cr Alloy |
Author(s) |
Fei Xue, Emmanuelle A. Marquis |
On-Site Speaker (Planned) |
Fei Xue |
Abstract Scope |
Surface deformation of Cr-containing alloys often improves their oxidation resistance at low and intermediate temperatures. This effect was previously attributed to fast diffusion along high densities of dislocations and stationary grain boundaries, despite rapid recovery/recrystallization. To elucidate the mechanism behind the beneficial effect of deformation, an electropolished and a ground Ni-30at.%Cr alloy were oxidized in air at 600 °C. The electropolished surface produced an uneven duplex scale with nodules consisting of external NiO and internal Cr2O3 oxides with Cr depletion beneath the scale consistent by limited bulk diffusion. Alternatively, the ground surface generated a uniformly thin single oxide Cr2O3 layer. In this case, the contribution of dislocations remained limited since recovery/recrystallization occurred within minutes. Instead, diffusion-induced grain boundary migration (DIGM) promoted by sub-surface recrystallization enabled rapid Cr diffusion to the surface. The impacts and implications of DIGM on the oxidation response of alloys will be discussed. |
Proceedings Inclusion? |
Planned: |
Keywords |
Characterization, Environmental Effects, High-Temperature Materials |