Effects of laser shock processing on θ-Al2O3 to α-Al2O3 transformation and oxide scale morphology evolution in (γ’+β) two-phase Ni-34Al-0.1Dy alloys
| Autor: | Jian He, Hongbo Guo, Bangyang Zhou, Qijie Zhou |
|---|---|
| Rok vydání: | 2022 |
| Předmět: |
Materials science
Polymers and Plastics Mechanical Engineering Alloy Metals and Alloys Nucleation Oxide engineering.material Grain size Superalloy chemistry.chemical_compound Chemical engineering chemistry Mechanics of Materials Phase (matter) Materials Chemistry Ceramics and Composites Surface roughness engineering Dislocation |
| Zdroj: | Journal of Materials Science & Technology. 109:157-166 |
| ISSN: | 1005-0302 |
| DOI: | 10.1016/j.jmst.2021.09.028 |
| Popis: | (γ’+β) two-phase Ni-Al is a promising high-temperature protective coating material used on Ni-base superalloys since it has good interfacial compatibility with superalloys due to the low Al content compared to single-phase β-NiAl. In this paper, we aim to improve the oxidation resistance, whereby Ni-34Al-0.1Dy, a (γ’+β) two-phase Ni-Al alloy, was treated by laser shock processing (LSP) and the oxidation behavior at 1150 °C was investigated. The results showed that after oxidation, Al2O3 scale formed on the original β phase of the untreated alloy with a small grain size (200-800 nm), while for the LSP-treated samples, the scale grown on the original β phase was dominantly composed of larger Al2O3 grains with a size of 2-3 μm. The distinction was attributed to the promotion of θ-Al2O3 to α-Al2O3 transformation induced by the LSP, because the dislocation density, as well as surface roughness, were increased during LSP treatment which can provide heterogeneous nucleation sites for α-Al2O3. In addition, the larger-size Al2O3 particles, derived from the direct conversion of needle-like θ-Al2O3 in the initial oxidation stage, could rapidly overspread the whole β phase surface thus reducing the scale growth rate. |
| Databáze: | OpenAIRE |
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