Changes in electrochemical properties of directionally solidified nibase superalloy due to creep and damage evaluation

Shin Ichi Komazaki, Tetsuo Shoji, Tetsuya Takeichi, Minoru Sato

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Changes in electrochemical properties of directionally solidified Ni-base superalloy CM 247 LC due to creep have been investigated. The electrochemical polarization technique has been applied to creep-ruptured and creep-interrupted specimens under various creep condition in order to examine a detectability of creep damage. Experimental results on electrochemical polarization measurements revealed that the peak current density "Ip" and "Ipr" which appeared at a specific potential during potentiodynamic polarization reactivation measurements in dilute glyceregia solution increased with increased thermal history and showed a good correlation with Larson-Miller Parameter value, Ip and Ipr value reflected both a thermal aging effect and a stress effect, and increased with a creep life fraction. The increases in Ip and Ipr were mainly corresponded to increases in preferential dissolution rate of γ phase at γ/γ interface. This preferential dissolution was considered as a result from degradation of corrosion resistance of γ phase at γ/γ interface which may be attributable to creep damage accumulation. As a consequence, the creep damage in CM 247 LC can be quantitatively evaluated by the electrochemical technique.

Original languageEnglish
Pages (from-to)1997-2001
Number of pages5
JournalNihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A
Volume64
Issue number623
DOIs
Publication statusPublished - 1998

Keywords

  • Creep
  • Creep damage evaluation
  • Directionally solidified Ni-base superalloy
  • Electrochemical property
  • Electrochemistry
  • Nondestructive inspection
  • γ-Channel
  • γ/γ Interface
  • γPhase

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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