2026-09-18T23:41:15Zhttps://dspace.mit.edu/server/oai/requestoai:dspace.mit.edu:1721.1/336132022-01-13T07:54:33Zcom_1721.1_7582com_1721.1_7581col_1721.1_131023
Ronald G. Ballinger.
Soontrapa, Chaiyod
Massachusetts Institute of Technology. Dept. of Materials Science and Engineering.
Massachusetts Institute of Technology. Department of Materials Science and Engineering
2006-07-31T15:17:08Z
2006-07-31T15:17:08Z
2005
2005
http://hdl.handle.net/1721.1/33613
64387820
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2005.
Includes bibliographical references (p. 57-59).
This study explores the possibility of extending the Ph.D. work of Yan Xu on copper-tin alloys (University of Pennsylvania, 1999) to model stress accelerated grain boundary oxidation (SAGBO) in INCOLOY alloy 908. The steady state model involves the embrittlement along the grain boundary due to oxygen diffusion with the concentration gradient and the stress field ahead of the crack tip as the driving forces. As oxygen forms brittle phases with the segregates in the grain boundary, it reduces the cohesive strength of the grain boundary and causes intergranular cracking in the material. The extensions to the original model include (1) dependence of oxygen concentration at crack tips on oxygen partial pressure and (2) a new creep law specific to nickel-based superalloys. While the steady state model correctly indicates temperature as one of three leading factors in SAGBO, it fails to capture the effects of the two remaining factors: applied loading and oxygen partial pressure.
by Chaiyod Soontrapa.
S.M.
59 p.
2139643 bytes
2142021 bytes
application/pdf
application/pdf
eng
Massachusetts Institute of Technology
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http://dspace.mit.edu/handle/1721.1/7582
Materials Science and Engineering.
Modeling stress accelerated grain boundary oxidation (SAGBO) in INCOLOY alloy 908
Modeling SAGBO in INCOLOY alloy 908
Thesis
application/pdf
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Publication
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<Abstract>This study explores the possibility of extending the Ph.D. work of Yan Xu on copper-tin alloys (University of Pennsylvania, 1999) to model stress accelerated grain boundary oxidation (SAGBO) in INCOLOY alloy 908. The steady state model involves the embrittlement along the grain boundary due to oxygen diffusion with the concentration gradient and the stress field ahead of the crack tip as the driving forces. As oxygen forms brittle phases with the segregates in the grain boundary, it reduces the cohesive strength of the grain boundary and causes intergranular cracking in the material. The extensions to the original model include (1) dependence of oxygen concentration at crack tips on oxygen partial pressure and (2) a new creep law specific to nickel-based superalloys. While the steady state model correctly indicates temperature as one of three leading factors in SAGBO, it fails to capture the effects of the two remaining factors: applied loading and oxygen partial pressure.</Abstract>
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