Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1583201 | Materials Science and Engineering: A | 2008 | 7 Pages |
Abstract
Microstructural evolution including MC decomposition during thermal exposure in GTD 111 has been investigated. After standard heat treatment, polycrystalline GTD 111 specimens were thermally exposed up to 10,000 h in the temperature range of 871-982 °C. Quantitative and qualitative metallographic analyses have been carried out to identify distribution and composition of the existing phases. Growth rate of γⲠof the alloy was proportional to the 1/3 power of the exposed time. The activation energy calculated for γⲠcoarsening was 256 kJ/mol. MC carbides decomposed into η and M23C6 during thermal exposure at 871 and 927 °C rather than M23C6 and γâ². Precipitation of sigma (Ï) phase was observed in the vicinity of MC or M23C6 carbides, especially in the specimen exposed at 871 °C. Continuous γⲠand M23C6 film precipitated along the grain boundary and fine η within γ-γⲠeutectic pool dissolved during thermal exposure at 982 °C.
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Physical Sciences and Engineering
Materials Science
Materials Science (General)
Authors
Baig Gyu Choi, In Soo Kim, Doo Hyun Kim, Chang Yong Jo,