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Creep-rupture and fractographic analysis of Stirling engine superalloys tested in air and 15 MPa hydrogenA brief comparative analytical and microstructural evaluation of creep-rupture performance of two iron-base superalloys in air and 15 MPa of hydrogen, is presented. Creep rupture data are presented for the sheet alloy 19-9DL and the cast alloy XF-818, including temperature, initial stress, rupture life, minimum creep rate, time to reach one percent creep strain, and total elongation. In 19-9DL, both rupture life and minimum creep rate are more sharply dependent on small stress changes than in XF-818 in the given environment, and 19-9DL appears to become a more creep-resistant material with increasing Q (apparent activation energy) while the opposite is noted for XF-818. There appears to be no environmental effect on minimum creep rate for 19-9DL, whereas Q becomes less negative for XF-818 for 15 MPa of H2. Multiple cracks leading to rupture are observed on the fracture surfaces, with sheet specimens showing many more cracks close to the fracture surface than cast specimens.
Document ID
19860045303
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Bhattacharyya, S.
(IIT Research Institute Chicago, IL, United States)
Titran, R. H.
(NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
August 12, 2013
Publication Date
January 1, 1986
Subject Category
Metallic Materials
Accession Number
86A30041
Funding Number(s)
CONTRACT_GRANT: DEN3-217
Distribution Limits
Public
Copyright
Other

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