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Journal of Materials Science

, Volume 31, Issue 10, pp 2735–2740 | Cite as

The controlling effect of 0.05% hydrogen sulfide gaseous atmosphere on the accelerated fatigue failure of coated MM-002 nickel-base superalloy at 650 °C

  • E. Aghion
  • M. Walker
  • D. Eliezer
  • N. Comins
Papers

Abstract

A systematic study was carried out aimed at evaluating the environmental effects of H2S containing environment on the creep-fatigue failure of coated undirectionally solidified MM-002 nickel-base superalloy at high temperature. The cyclic loading conditions were constant and consisted of creep tension and plastic compression following the CP-mode of the strain range partitioning method. The results obtained have shown that although the pack cementation coating used showed adequate resistance under the combination of cyclic loading and oxidizing environments, this resistance was not evident under the H2S containing atmosphere. In fact, it was found that even an amount as little as 0.05% H2S had an extremely detrimental effect on the creep-fatigue life of the coated superalloy at 650 °C. The crack initiation and propagation in the H2S environment was controlled by an aggressive sulphidation attack ahead of the crack tip. This was demonstrated by the formation of low melting eutectic sulfides at the plastic zone ahead of the crack tip, causing an accelerated transdendritic cracking and premature failure.

Keywords

Crack Initiation Cementation Hydrogen Sulfide Fatigue Failure Pack Cementation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Chapman & Hall 1996

Authors and Affiliations

  • E. Aghion
    • 1
  • M. Walker
    • 1
  • D. Eliezer
    • 2
  • N. Comins
    • 3
  1. 1.Department of Mechanical EngineeringUniversity of NatalDurbanSouth Africa
  2. 2.Department of Materials EngineeringBen-Gurion UniversityBeer-ShevaIsrael
  3. 3.Division of Materials Science and TechnologyCSIRPretoriaSouth Africa

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