Influence of Strain Amplitude on Low-Cycle Fatigue Behaviors of a Fourth-Generation Ni-Based Single-Crystal Superalloy at 980 °C
Total strain-control, low-cycle fatigue experiments of a fourth-generation Ni-based single-crystal superalloy were performed at 980 °C. Scanning electron microscopy and transmission electron microscopy are employed to determine fracture morphologies and dislocation characteristics of the samples. As...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-04-01
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| Series: | Crystals |
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| Online Access: | https://www.mdpi.com/2073-4352/13/4/686 |
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| author | Pengfei Wang Xinbao Zhao Quanzhao Yue Wanshun Xia Qingqing Ding Hongbin Bei Yuefeng Gu Yuefei Zhang Ze Zhang |
| author_facet | Pengfei Wang Xinbao Zhao Quanzhao Yue Wanshun Xia Qingqing Ding Hongbin Bei Yuefeng Gu Yuefei Zhang Ze Zhang |
| author_sort | Pengfei Wang |
| collection | DOAJ |
| description | Total strain-control, low-cycle fatigue experiments of a fourth-generation Ni-based single-crystal superalloy were performed at 980 °C. Scanning electron microscopy and transmission electron microscopy are employed to determine fracture morphologies and dislocation characteristics of the samples. As the strain amplitude increased from 0.6 to 1.0%, the cyclic stress and plastic strain per cycle increased, the cyclic lifetime decreased, more interfacial dislocation networks were formed, and the formation rate accelerated. Cyclic hardening is associated with the reaction of accumulated dislocations and dislocation networks, which hinder the movement of dislocations. The presence of interfacial dislocations reduces the lattice mismatch between the γ and γ′ phases, and the presence of dislocation networks that absorb mobile dislocations results in cyclic softening. At a strain amplitude of 1.0%, the reaction of a high density of dislocations results in initial cyclic hardening, and the dislocation cutting into the γ′ phase is one of the reasons for cyclic softening. The crack initiation site changed from a near-surface defect to a surface defect when the strain amplitude increased from 0.6 to 0.8 to 1.0%. The number of secondary cracks initiated from the micropores decreased during the growth stage as the strain amplitude increased. |
| first_indexed | 2024-03-11T05:06:40Z |
| format | Article |
| id | doaj.art-064bf9e447764b65826987fc52870100 |
| institution | Directory Open Access Journal |
| issn | 2073-4352 |
| language | English |
| last_indexed | 2024-03-11T05:06:40Z |
| publishDate | 2023-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Crystals |
| spelling | doaj.art-064bf9e447764b65826987fc528701002023-11-17T18:52:03ZengMDPI AGCrystals2073-43522023-04-0113468610.3390/cryst13040686Influence of Strain Amplitude on Low-Cycle Fatigue Behaviors of a Fourth-Generation Ni-Based Single-Crystal Superalloy at 980 °CPengfei Wang0Xinbao Zhao1Quanzhao Yue2Wanshun Xia3Qingqing Ding4Hongbin Bei5Yuefeng Gu6Yuefei Zhang7Ze Zhang8Institute of Superalloys Science and Technology, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, ChinaInstitute of Superalloys Science and Technology, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, ChinaInstitute of Superalloys Science and Technology, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, ChinaInstitute of Superalloys Science and Technology, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, ChinaInstitute of Superalloys Science and Technology, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, ChinaInstitute of Superalloys Science and Technology, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, ChinaInstitute of Superalloys Science and Technology, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, ChinaInstitute of Superalloys Science and Technology, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, ChinaInstitute of Superalloys Science and Technology, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, ChinaTotal strain-control, low-cycle fatigue experiments of a fourth-generation Ni-based single-crystal superalloy were performed at 980 °C. Scanning electron microscopy and transmission electron microscopy are employed to determine fracture morphologies and dislocation characteristics of the samples. As the strain amplitude increased from 0.6 to 1.0%, the cyclic stress and plastic strain per cycle increased, the cyclic lifetime decreased, more interfacial dislocation networks were formed, and the formation rate accelerated. Cyclic hardening is associated with the reaction of accumulated dislocations and dislocation networks, which hinder the movement of dislocations. The presence of interfacial dislocations reduces the lattice mismatch between the γ and γ′ phases, and the presence of dislocation networks that absorb mobile dislocations results in cyclic softening. At a strain amplitude of 1.0%, the reaction of a high density of dislocations results in initial cyclic hardening, and the dislocation cutting into the γ′ phase is one of the reasons for cyclic softening. The crack initiation site changed from a near-surface defect to a surface defect when the strain amplitude increased from 0.6 to 0.8 to 1.0%. The number of secondary cracks initiated from the micropores decreased during the growth stage as the strain amplitude increased.https://www.mdpi.com/2073-4352/13/4/686deformation behaviorslow-cycle fatiguesingle-crystal superalloysstrain amplitude |
| spellingShingle | Pengfei Wang Xinbao Zhao Quanzhao Yue Wanshun Xia Qingqing Ding Hongbin Bei Yuefeng Gu Yuefei Zhang Ze Zhang Influence of Strain Amplitude on Low-Cycle Fatigue Behaviors of a Fourth-Generation Ni-Based Single-Crystal Superalloy at 980 °C Crystals deformation behaviors low-cycle fatigue single-crystal superalloys strain amplitude |
| title | Influence of Strain Amplitude on Low-Cycle Fatigue Behaviors of a Fourth-Generation Ni-Based Single-Crystal Superalloy at 980 °C |
| title_full | Influence of Strain Amplitude on Low-Cycle Fatigue Behaviors of a Fourth-Generation Ni-Based Single-Crystal Superalloy at 980 °C |
| title_fullStr | Influence of Strain Amplitude on Low-Cycle Fatigue Behaviors of a Fourth-Generation Ni-Based Single-Crystal Superalloy at 980 °C |
| title_full_unstemmed | Influence of Strain Amplitude on Low-Cycle Fatigue Behaviors of a Fourth-Generation Ni-Based Single-Crystal Superalloy at 980 °C |
| title_short | Influence of Strain Amplitude on Low-Cycle Fatigue Behaviors of a Fourth-Generation Ni-Based Single-Crystal Superalloy at 980 °C |
| title_sort | influence of strain amplitude on low cycle fatigue behaviors of a fourth generation ni based single crystal superalloy at 980 °c |
| topic | deformation behaviors low-cycle fatigue single-crystal superalloys strain amplitude |
| url | https://www.mdpi.com/2073-4352/13/4/686 |
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