Improving the hot corrosion resistance of precipitation strengthened nickel-based superalloy formed by laser powder bed fusion at 750 °C via tailoring microstructure
In this study, the microstructure of spherical γ′ phases and annealing twins was obtained by solid solution and aging treatment in laser powder bed melting forming nickel-based superalloy, and the hot corrosion behavior and hot corrosion mechanism of the alloy sample in 75 wt% Na2SO4 + 25 wt% NaCl m...
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| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-05-01
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| Series: | Journal of Materials Research and Technology |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785425012840 |
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| Summary: | In this study, the microstructure of spherical γ′ phases and annealing twins was obtained by solid solution and aging treatment in laser powder bed melting forming nickel-based superalloy, and the hot corrosion behavior and hot corrosion mechanism of the alloy sample in 75 wt% Na2SO4 + 25 wt% NaCl mixed salt at 750 °C were studied. The results show that compared with the as-deposited sample, the sample with γ′ phase and annealing twin structure (1190SA) improves the hot corrosion resistance of the alloy. At the same time, the smaller the γ′ phase and the higher the annealing twin content, the better the hot corrosion resistance. This is mainly because the γ′ phase and annealing twin structure provide a fast channel for the outward diffusion of Al and Cr elements, hinder the inward diffusion of S elements, and promote the rapid formation of three-layer continuity. A dense oxide layer (Cr2O3–TiO–Al2O3), shallow sulfide layer and matrix zone without corrosion defects such as micropores constitute a corrosion layer. The dense oxide layer hinders the further diffusion of corrosive medium elements into the matrix, which significantly affects the hot corrosion resistance of the alloy samples. In addition, it is also found that the hot corrosion mechanism of S, O and Cl elements in the hot corrosion process is a synergistic process involving acid-base melting and internal sulfurization. |
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| ISSN: | 2238-7854 |