| Title |
Microstructural Evolutions of 22Cr-9Mo-3Fe-4Nb Nickel-Base Superalloy During Low Cycle Fatigue |
| Authors |
송영석(Youngseok Song); 석진익(Jinik Suk); 강정윤(Chung Yun Kang) |
| DOI |
https://doi.org/10.3365/KJMM.2017.55.9.609 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
alloys; forging; fatigue; microstructure; carbides; transmission electron microscopy |
| Abstract |
Abstract: 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.(Received March 7, 2017; Accepted June 7, 2017) |