| 22Cr-9Mo-3Fe-4Nb 니켈기 초내열합금의 저주기 피로에 따른 미세조직변화 |
| 송영석1, 석진익1, 강정윤2 |
1두산중공업 소재기술개발팀
2부산대학교 재료공학부 |
| Microstructural Evolutions of 22Cr-9Mo-3Fe-4Nb Nickel-Base Superalloy During Low Cycle Fatigue |
| Youngseok Song1, Jinik Suk1, Chung Yun Kang2 |
1Materials Development Team, Doosan Heavy Industries & Construction, Changwon 51711, Republic of Korea
2Department of Materials Engineering, Pusan National University, Busan 46287, Republic of Korea |
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Received: 7 March 2017; Accepted: 7 June 2017. Published online: 30 August 2017. |
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| ABSTRACT |
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A new Ni based superalloy with high fatigue resistance and fine grain was considered as a material for high-pressure buckets in fossil fuel power plants. Since such buckets are usually exposed to extreme operating conditions, low cycle fatigue tests were conducted to understand the microstructure evolution of the material during cyclic fatigue under total strains of 0.8, 0.9, 1.0 and 1.2%, and temperatures of 566, 593, 621, 649 and 700 ℃. Microstructural analysis of fractured specimens was conducted using TEM, SEM and OM to observe changes in the γ΄΄ morphology, carbides, and fracture mode. Based on the observations of microstructural changes and low cycle fatigue properties, it can be concluded that grain size had the dominant effect on low cycle fatigue properties, regardless of the size of the transformed carbides and precipitates in these alloy systems. |
| Keywords:
alloys, forging, fatigue, microstructure, carbides, transmission electron microscopy |
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