Creep damage evaluation of W alloyed 9%Cr ferritic steel by electrochemical method

S. Komazaki, S. Kishi, T. Shoji, K. Higuchi, K. Suzuki

研究成果: Article査読

5 被引用数 (Scopus)

抄録

In order to develop a methodology for creep damage evaluation of W alloyed 9%Cr ferritic steel KA-STBA29/ KA-STPA29 (ASME T92/P92), which is the candidate material for an ultra-super-critical fossil power plant, changes in electrochemical property of the steel caused by creep have been investigated. Experimental results on electrochemical polarization measurements revealed that the peak current density "Ip", which appeared at a specific potential during potentiodynamic polarization measurement in 1N-KOH solution, increased with thermal aging and creep damage and reflected not only the thermal effect but also the stress effect on creep damage. The Ip value corresponded to the selective dissolution volume of precipitates (M23C6 and Laves phase) and the increase in the Ip due to creep damage reflected the increase in amount of chromium precipitated as Laves phase. It was found that the difference in the Ip value between the as-tempered material and the creep damaged materials (ΔIp) were uniquely correlated with a newly proposed parameter "t · F(T) · exp(-Q(σ)/RT)" irrespective of test conditions, which is the parameter based on Laves phase precipitation kinetics. On the basis of such correlation between ΔIp and t · F(T) · exp(-Q(σ)/RT), the test temperature or the applied stress of the creep damaged materials can be nondestructively estimated by electrochemical polarization measurements.

本文言語English
ページ(範囲)503-509
ページ数7
ジャーナルZairyo/Journal of the Society of Materials Science, Japan
50
5
DOI
出版ステータスPublished - 2001 5月

ASJC Scopus subject areas

  • 材料科学(全般)
  • 凝縮系物理学
  • 材料力学
  • 機械工学

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