A Mechanistic Study of the Effect of Temperature on Crack Propagation in Alloy 600 Under PWR Primary Water Conditions
Stress corrosion cracking (SCC) in Alloy 600 has been studied in simulated pressurized water reactor (PWR) primary water at various temperatures. A clear correlation between temperature and crack growth rate (CGR) was found showing that the CGR increased monotonously within the range of temperatures used in this study (320–360 °C). In order to understand the temperature dependence of CGR, high-resolution characterization was used to study the crack tips. The crack tips obtained from different temperatures were analyzed by high-resolution analytical transmission electron microscopy (TEM) to reveal the crack tip morphology and chemistry, which enable the study of a thermally activated diffusion-based mechanism operating during SCC propagation. Transmission Kikuchi diffraction (TKD) was used to investigate mechanical response-based mechanisms in SCC propagation through quantifying the size and extent of plastic deformation around the crack tips. Results obtained in this study show that the thermally activated diffusion along the grain boundary increased with temperature while the changes of plastic deformation around the crack tip were small and nearly independent of temperature, suggesting that a thermally activated diffusion-based mechanism was dominant.
KeywordsStress corrosion cracking Temperature dependence Crack growth rate Alloy 600 Transmission electron microscopy Transmission kikuchi diffraction
The authors would like to thank Koji Arioka (INSS) for providing the samples used in this study and for useful discussions. Zhao Shen is also grateful to China Scholarship Council for providing financial support. The EPSRC (EP/K040375/1) is acknowledged for funding the ‘South of England Analytical Electron Microscope’ used in this research.
- 1.H. Coriou, L. Crall, Y. L. Gall, S. Vettier, in 3rd Metallurgy Conference on Corrosion, Saclay (Amsterdam, The Netherlands: North Holland Publishing Co., 1959), 1960 pp. 161–169Google Scholar
- 2.W. Bamford, J. Hall, in Proceedings of the 12th Int’l Conference on Environmental Degradation of Materials in Nuclear Power Systems—Water Reactor, Salt Lake City, UT, 2005, p. 959Google Scholar
- 5.S. Lozano-Perez, K. Kruska, I. Iyengar, T. Terachi, T. Yamada, The role of cold work and applied stress on surface oxidation of 304 stainless steel. CorrosionScience 56, 78–85 (2012)Google Scholar
- 16.P.M. Scott, M. Le Calver, Some possible mechanisms of intergranular stress corrosion cracking of alloy 600 in PWR primary water, in Proceedings of the sixth international symposium on environmental degradation of materials in nuclear power systems-water reactors. (TMS, 1993), pp. 657–665Google Scholar
- 17.S. Lozano-Perez, J. Dohr, M. Meisnar, K. Kruska, SCC in PWRs: Learning from a bottom-up approach. Metall. Mater. Trans. E 1, 194–210 (2014)Google Scholar
- 23.P.L. Andresen, L.M. Young, P.W. Emigh, R.M. Horn, Stress corrosion crack growth rate behavior of Ni alloys 182 and 600 in high temperature water, in Proceedings of Corrosion 2002, Paper no.2510, NACE, 2002Google Scholar
- 24.T. Shoji, G. Li, J. Kwon, S. Matsushima, Quantification of yield strength effects on IGSCC of austenitic stainless steels in high temperature water, in Proceedings of 11th International Conference on Environmental Degradation of Materials in Nuclear Power Systems-Water Reactors, Stevenson, 10–14 Aug 2003Google Scholar