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Sulfur embrittlement on [gamma]/[gamma]' interface of Ni-base single crystal superalloys

From National Research Council Canada

DOIResolve DOI: https://doi.org/10.1016/S1359-6454(02)00512-8
AuthorSearch for: 1; Search for: 1; Search for: 1
Affiliation
  1. National Research Council Canada. NRC Institute for Aerospace Research
FormatText, Article
Subject[gamma]/[gamma]' interface; First principles calculations; Ni-base superalloys; Sulfur embrittlement; Impurity sulfur
Abstract
The impurity sulfur embrittlement on [gamma]/[gamma]' interface of Ni-base single crystal superalloys has been investigated by first principles quantum mechanics DMol calculations. Using a local sum of vertical ([summation operator]BOv) and horizontal ([summation operator]BOh) Mayer bond orders, we proposed a new method to evaluate the competition between the shear and cohesive strengths of the interface. Coupled with the phenomenological theory of fracture, we define the ratio of RBO=[summation operator]BOh/[summation operator]BOv to assess the embrittlement trend of the interface related to sulfur doping or sulfur doping combined with Re substitution. It is shown that sulfur increases RBO by 121% relative to the sulfur-free [gamma]/[gamma]' interface, which could induce interface embrittlement from the electron bonding point of view. Calculations of both BO and charge density distribution reveal that it is the strong bonds between sulfur and Ni atoms lying within the interface that contribute to the interface embrittlement. The substitution of Re for Al at the [gamma]/[gamma]' interface results in reduced RBO, thus relieving the tendency of interface embrittlement. Furthermore, our model on sulfur embrittlement is compared with previous models.
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In
  • Acta Materialia 51, no. 4 (February 2003): 1079–1086.
LanguageEnglish
NRC numberSMPL-2002-0069
NPARC number12338214
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Record identifierd12b87b7-78bf-42d0-b34f-16e587251d00
Record created2009-09-10
Record modified2020-04-02
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