Microstructural Evolution of a Re-Containing 10% Cr-3Co-3W Steel during Creep at Elevated Temperature
Ten percent Cr steels are considered to be prospective materials for the production of pipes, tubes, and blades in coal-fired power plants, which are able to operate within ultra-supercritical steam parameters. The microstructural evolution of a Re-containing 10% Cr-3Co-3W steel with low N and high...
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| Format: | Article |
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MDPI AG
2023-10-01
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| Series: | Metals |
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| Online Access: | https://www.mdpi.com/2075-4701/13/10/1683 |
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| author | Alexandra Fedoseeva Ivan Brazhnikov Svetlana Degtyareva Ivan Nikitin Rustam Kaibyshev |
| author_facet | Alexandra Fedoseeva Ivan Brazhnikov Svetlana Degtyareva Ivan Nikitin Rustam Kaibyshev |
| author_sort | Alexandra Fedoseeva |
| collection | DOAJ |
| description | Ten percent Cr steels are considered to be prospective materials for the production of pipes, tubes, and blades in coal-fired power plants, which are able to operate within ultra-supercritical steam parameters. The microstructural evolution of a Re-containing 10% Cr-3Co-3W steel with low N and high B content during creep was investigated at different strains at 923 K and under an applied stress of 120 MPa using TEM and EBSD analyses. The studied steel had been previously normalized at 1323 K and tempered at 1043 K for 3 h. In the initial state, the tempered martensite lath structure with high dislocation density was stabilized by M<sub>23</sub>C<sub>6</sub> carbides, NbX carbonitrides, and M<sub>6</sub>C carbides. At the end of the primary creep stage, the main microstructural change was found to be the precipitation of the fine Laves phase particles along the boundaries of the prior austenite grains, packets, blocks, and martensitic laths. The remarkable microstructural degradation processes, such as the significant growth of martensitic laths, the reduction in dislocation density within the lath interiors, and the growth of the grain boundary Laves phase particles, occurred during the steady-state and tertiary creep stages. Moreover, during the steady-state creep stage, the precipitation of the V-rich phase was revealed. Softening was in accordance with the dramatic reduction in hardness during the transition from the primary creep stage to the steady-state creep stage. The reasons for the softening were considered to be due to the change in the strengthening mechanisms and the interactions of the grain boundary M<sub>23</sub>C<sub>6</sub> carbides and Laves phase with the low-angle boundaries of the martensitic laths and free dislocations. |
| first_indexed | 2024-03-10T21:03:40Z |
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| id | doaj.art-92270c90acf5495885d4134078629f3c |
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| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-10T21:03:40Z |
| publishDate | 2023-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Metals |
| spelling | doaj.art-92270c90acf5495885d4134078629f3c2023-11-19T17:21:25ZengMDPI AGMetals2075-47012023-10-011310168310.3390/met13101683Microstructural Evolution of a Re-Containing 10% Cr-3Co-3W Steel during Creep at Elevated TemperatureAlexandra Fedoseeva0Ivan Brazhnikov1Svetlana Degtyareva2Ivan Nikitin3Rustam Kaibyshev4Laboratory of Mechanical Properties of Nanostructured Materials and Superalloys, Belgorod National Research University, Pobeda 85, 308015 Belgorod, RussiaLaboratory of Mechanical Properties of Nanostructured Materials and Superalloys, Belgorod National Research University, Pobeda 85, 308015 Belgorod, RussiaLaboratory of Mechanical Properties of Nanostructured Materials and Superalloys, Belgorod National Research University, Pobeda 85, 308015 Belgorod, RussiaLaboratory of Mechanical Properties of Nanostructured Materials and Superalloys, Belgorod National Research University, Pobeda 85, 308015 Belgorod, RussiaLaboratory of Prospective Steels for Agricultural Machinery, Russian State Agrarian University—Moscow Timiryazev Agricultural Academy, Timiryazevskaya, 49, 127550 Moscow, RussiaTen percent Cr steels are considered to be prospective materials for the production of pipes, tubes, and blades in coal-fired power plants, which are able to operate within ultra-supercritical steam parameters. The microstructural evolution of a Re-containing 10% Cr-3Co-3W steel with low N and high B content during creep was investigated at different strains at 923 K and under an applied stress of 120 MPa using TEM and EBSD analyses. The studied steel had been previously normalized at 1323 K and tempered at 1043 K for 3 h. In the initial state, the tempered martensite lath structure with high dislocation density was stabilized by M<sub>23</sub>C<sub>6</sub> carbides, NbX carbonitrides, and M<sub>6</sub>C carbides. At the end of the primary creep stage, the main microstructural change was found to be the precipitation of the fine Laves phase particles along the boundaries of the prior austenite grains, packets, blocks, and martensitic laths. The remarkable microstructural degradation processes, such as the significant growth of martensitic laths, the reduction in dislocation density within the lath interiors, and the growth of the grain boundary Laves phase particles, occurred during the steady-state and tertiary creep stages. Moreover, during the steady-state creep stage, the precipitation of the V-rich phase was revealed. Softening was in accordance with the dramatic reduction in hardness during the transition from the primary creep stage to the steady-state creep stage. The reasons for the softening were considered to be due to the change in the strengthening mechanisms and the interactions of the grain boundary M<sub>23</sub>C<sub>6</sub> carbides and Laves phase with the low-angle boundaries of the martensitic laths and free dislocations.https://www.mdpi.com/2075-4701/13/10/1683high-chromium steelscreepmicrostructural evolutionsofteningstrengthening mechanismZener pressure |
| spellingShingle | Alexandra Fedoseeva Ivan Brazhnikov Svetlana Degtyareva Ivan Nikitin Rustam Kaibyshev Microstructural Evolution of a Re-Containing 10% Cr-3Co-3W Steel during Creep at Elevated Temperature Metals high-chromium steels creep microstructural evolution softening strengthening mechanism Zener pressure |
| title | Microstructural Evolution of a Re-Containing 10% Cr-3Co-3W Steel during Creep at Elevated Temperature |
| title_full | Microstructural Evolution of a Re-Containing 10% Cr-3Co-3W Steel during Creep at Elevated Temperature |
| title_fullStr | Microstructural Evolution of a Re-Containing 10% Cr-3Co-3W Steel during Creep at Elevated Temperature |
| title_full_unstemmed | Microstructural Evolution of a Re-Containing 10% Cr-3Co-3W Steel during Creep at Elevated Temperature |
| title_short | Microstructural Evolution of a Re-Containing 10% Cr-3Co-3W Steel during Creep at Elevated Temperature |
| title_sort | microstructural evolution of a re containing 10 cr 3co 3w steel during creep at elevated temperature |
| topic | high-chromium steels creep microstructural evolution softening strengthening mechanism Zener pressure |
| url | https://www.mdpi.com/2075-4701/13/10/1683 |
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