Microstructure evolution in GH4742 superalloy by combining hot deformation and heat treatment
The microstructure evolution of GH4742 superalloy under the coupling action of hot deformation and heat treatment was studied by isothermal compression and then solvus heat treatment (SHT), with particular attention focused on the interaction mechanism between γ′ precipitates and dynamic recrystalli...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2023-03-01
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| Series: | Journal of Materials Research and Technology |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785422020841 |
| _version_ | 1827978386435211264 |
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| author | Wenwen Zhang Xingang Liu Qiang Du Ying Guo Heyong Qin Qiang Tian Mengying Zhu |
| author_facet | Wenwen Zhang Xingang Liu Qiang Du Ying Guo Heyong Qin Qiang Tian Mengying Zhu |
| author_sort | Wenwen Zhang |
| collection | DOAJ |
| description | The microstructure evolution of GH4742 superalloy under the coupling action of hot deformation and heat treatment was studied by isothermal compression and then solvus heat treatment (SHT), with particular attention focused on the interaction mechanism between γ′ precipitates and dynamic recrystallization (DRX) grains. The deformation of material below the γ′ solvus temperature (1020–1050 °C) by DRX was retarded because of the strong pinning effect of γ′ precipitates. At a strain of 0.6 and all strain rates (0.01–1 s−1), a necklace-like microstructure formed with fine DRXed grains (∼2 μm) and a small DRXed fraction (<20%). The γ′ precipitates dissolved with the migration of DRX grain boundaries (GBs), and there were no secondary γ′ precipitates within DRXed grains. During sub-solvus heat treatment (sub-SHT) of pre-deformed samples below the γ′ solvus temperature, the nucleation rate of post dynamic recrystallization (PDRX) increased significantly (30–50%), and the recrystallized grains were small (∼10 μm) due to a large amount of energy stored after thermal deformation. Rod-shaped γ′ precipitates appeared on the DRXed GBs, while coarse γ′ precipitates (3–5 μm) appeared on the PDRXed GBs and formed an approximate γ+γ′ duplex structure. When the strain was 0.6, regardless of changes in the strain rate (0.01–1 s−1) and temperature (1020–1140 °C) of pre-deformed samples, the microstructure was comprised of large, equiaxed grains with straight GBs and precipitates (20 nm) formed by cooling during super-solvus treatment (super-SHT). |
| first_indexed | 2024-04-09T21:20:03Z |
| format | Article |
| id | doaj.art-f30102b9d92e45589d8891fba295472b |
| institution | Directory Open Access Journal |
| issn | 2238-7854 |
| language | English |
| last_indexed | 2024-04-09T21:20:03Z |
| publishDate | 2023-03-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Materials Research and Technology |
| spelling | doaj.art-f30102b9d92e45589d8891fba295472b2023-03-28T06:45:41ZengElsevierJournal of Materials Research and Technology2238-78542023-03-01231335Microstructure evolution in GH4742 superalloy by combining hot deformation and heat treatmentWenwen Zhang0Xingang Liu1Qiang Du2Ying Guo3Heyong Qin4Qiang Tian5Mengying Zhu6College of Mechanical Engineering, Yanshan University, Qinhuangdao 066004, Hebei, ChinaCollege of Mechanical Engineering, Yanshan University, Qinhuangdao 066004, Hebei, China; Corresponding author.College of Mechanical Engineering, Yanshan University, Qinhuangdao 066004, Hebei, ChinaGraduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima, 739-8527, JapanHigh Temperature Materials Research Division, Central Iron & Steel Research Institute, Beijing 100081, ChinaHigh Temperature Materials Research Division, Central Iron & Steel Research Institute, Beijing 100081, ChinaCollege of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004, ChinaThe microstructure evolution of GH4742 superalloy under the coupling action of hot deformation and heat treatment was studied by isothermal compression and then solvus heat treatment (SHT), with particular attention focused on the interaction mechanism between γ′ precipitates and dynamic recrystallization (DRX) grains. The deformation of material below the γ′ solvus temperature (1020–1050 °C) by DRX was retarded because of the strong pinning effect of γ′ precipitates. At a strain of 0.6 and all strain rates (0.01–1 s−1), a necklace-like microstructure formed with fine DRXed grains (∼2 μm) and a small DRXed fraction (<20%). The γ′ precipitates dissolved with the migration of DRX grain boundaries (GBs), and there were no secondary γ′ precipitates within DRXed grains. During sub-solvus heat treatment (sub-SHT) of pre-deformed samples below the γ′ solvus temperature, the nucleation rate of post dynamic recrystallization (PDRX) increased significantly (30–50%), and the recrystallized grains were small (∼10 μm) due to a large amount of energy stored after thermal deformation. Rod-shaped γ′ precipitates appeared on the DRXed GBs, while coarse γ′ precipitates (3–5 μm) appeared on the PDRXed GBs and formed an approximate γ+γ′ duplex structure. When the strain was 0.6, regardless of changes in the strain rate (0.01–1 s−1) and temperature (1020–1140 °C) of pre-deformed samples, the microstructure was comprised of large, equiaxed grains with straight GBs and precipitates (20 nm) formed by cooling during super-solvus treatment (super-SHT).http://www.sciencedirect.com/science/article/pii/S2238785422020841GH4742 superalloySub-solvus heat treatmentSuper-solvus heat treatmentγ′ precipitatesDynamic recrystallizationγ+γ′ duplex structures |
| spellingShingle | Wenwen Zhang Xingang Liu Qiang Du Ying Guo Heyong Qin Qiang Tian Mengying Zhu Microstructure evolution in GH4742 superalloy by combining hot deformation and heat treatment Journal of Materials Research and Technology GH4742 superalloy Sub-solvus heat treatment Super-solvus heat treatment γ′ precipitates Dynamic recrystallization γ+γ′ duplex structures |
| title | Microstructure evolution in GH4742 superalloy by combining hot deformation and heat treatment |
| title_full | Microstructure evolution in GH4742 superalloy by combining hot deformation and heat treatment |
| title_fullStr | Microstructure evolution in GH4742 superalloy by combining hot deformation and heat treatment |
| title_full_unstemmed | Microstructure evolution in GH4742 superalloy by combining hot deformation and heat treatment |
| title_short | Microstructure evolution in GH4742 superalloy by combining hot deformation and heat treatment |
| title_sort | microstructure evolution in gh4742 superalloy by combining hot deformation and heat treatment |
| topic | GH4742 superalloy Sub-solvus heat treatment Super-solvus heat treatment γ′ precipitates Dynamic recrystallization γ+γ′ duplex structures |
| url | http://www.sciencedirect.com/science/article/pii/S2238785422020841 |
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