Relationship Among Dislocation Density, Local Strain Distribution, and PWSCC Susceptibility of Alloy 690

  • Tae-Young Ahn
  • Sung-Woo Kim
  • Seong Sik Hwang
  • Hong-Pyo KimEmail author
Conference paper
Part of the The Minerals, Metals & Materials Series book series (MMMS)


The effects of local strain distribution on primary water stress corrosion cracking of cold-rolled Alloy 690 with an inhomogeneous microstructure were investigated by measuring dislocation densities using transmission electron microscopy. Many intragranular carbides with a Cr-rich M23C6 structure were dispersed in the fine grains. The results showed that the dislocation densities near the intragranular carbides were high, regardless of the degree of cold-rolling. Below 20% cold-rolling, the dislocation densities near grain boundaries were higher than that in the grain interior. Meanwhile, the dislocation densities in the grain interior increased to similar value of the grain boundary with increasing degree of cold-rolling up to 40%. The results indicate that the intragranular carbides dispersed in the fine grains play an important role in the local strain distribution of a cold-rolled Alloy 690 with an inhomogeneous microstructure. It is suggested that the high local strain in the grain interior in a severely cold-rolled Alloy 690 induced by interaction between dislocation and intragranular carbides could be responsible for the mixed cracking mode and the high crack growth rate.


Stress corrosion cracking Strain Transmission electron microscopy Dislocation 



This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Science, ICT & Future Planning (2017M2A8A4015155).


  1. 1.
    S.-W. Kim, S.-S. Hwang, J.-M. Lee, Effect of local distribution on stress corrosion cracking of cold-rolled Alloy 690 with inhomogeneous microstructure. Corrosion 71, 1071–1081 (2015)CrossRefGoogle Scholar
  2. 2.
    Y.S. Lim et al., Intergranular oxidation of Ni-based Alloy 600 in a simulated PWR primary water environment. Corros. Sci. 108, 125–133 (2016)CrossRefGoogle Scholar
  3. 3.
    S.M. Bruemmer et al., Linking grain boundary microstructure to stress corrosion cracking of cold-rolled Alloy 690 in pressurized water reactor primary water. Corrosion 69, 953–963 (2013)CrossRefGoogle Scholar
  4. 4.
    T. Yonezawa, M. Watanabe, A. Hasimoto, The effects of metallurgical factors on PWSCC crack growth rates in TT Alloy 690 in simulated PWR primary water. Metall. Mater. Trans. A 46A, 2768–2780 (2015)CrossRefGoogle Scholar
  5. 5.
    M. Tanaka et al., Crack tip dislocation revealed by electron tomography in silicon single crystal. Scripta Mater. 59, 901–904 (2008)CrossRefGoogle Scholar
  6. 6.
    R.K. Ham, The determination of dislocation densities in thin films. Phil. Mag. 6, 1183–1184 (1961)CrossRefGoogle Scholar
  7. 7.
    Y. Miyajima et al., Quantification of internal dislocation density using scanning transmission electron microscopy in ultrafine grained pure aluminium fabricated by severe plastic deformation. Mater. Sci. Eng. A 528, 776–779 (2010)CrossRefGoogle Scholar
  8. 8.
    T. Malis, S.C. Cheng, R.F. Egerton, EELS log-ratio technique for specimen-thickness measurement in the TEM. J. Electron Microsc. Tech. 8, 193–200 (1988)CrossRefGoogle Scholar
  9. 9.
    Y.S. Lim et al., M23C6 precipitation behavior and grain boundary serration in Ni-based Alloy 690. Mater. Charact. 96, 28–39 (2014)CrossRefGoogle Scholar
  10. 10.
    S.S. Hwang et al., Role of grain boundary carbides in cracking behavior of Ni base alloys. Nucl. Eng. Technol. 45, 73–80 (2013)CrossRefGoogle Scholar
  11. 11.
    S.M. Bruemmer, L.A. Charlot, C.H. Henager Jr, Microstructure and microdeformation effects on IGSCC Alloy 600 steam generator tubing. Corrosion 782–788 (1988)CrossRefGoogle Scholar
  12. 12.
    T.-Y. Ahn, S.S Hwang, S.-W. Kim, Local strain distribution and its effect on the PWSCC in cold-rolled Alloy 690 with inhomogeneous microstructure. Corros. Sci. SubmittedGoogle Scholar
  13. 13.
    S.-W. Kim et al, Effect of local distribution of cold-rolled Alloy 690 on primary water stress corrosion crack growth behavior. Arc. Metall. Mater. in press (2017)Google Scholar

Copyright information

© The Minerals, Metals & Materials Society 2019

Authors and Affiliations

  • Tae-Young Ahn
    • 1
  • Sung-Woo Kim
    • 1
  • Seong Sik Hwang
    • 1
  • Hong-Pyo Kim
    • 1
    Email author
  1. 1.Nuclear Materials Safety Research DivisionKorea Atomic Energy Research InstituteDaejeonRepublic of Korea

Personalised recommendations