Quantitative assessment of intergranular damage due to PWR primary water exposure in structural Ni-based alloys

Benoît Ter-Ovanessian (1) , Julien Deleume (2) , Jean-Marc Cloué (3) , Eric Andrieu (4)

1 MATEIS - Matériaux, ingénierie et science [Villeurbanne]
2 Centre de Recherche de CEZUS (Ugine, France)
3 AREVA NP
4 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux

Two nickel-based alloys, alloy 718 and alloy 600, known to have different resistances to IGSCC, were exposed to a simulated PWR primary water environment at 360 °C for 1000 h. The intergranular oxidation damage was analyzed in detail using an original approach involving two characterization methods (Incremental Mechanical Polishing/Microcopy procedure and SIMS imaging) which yielded a tomographic analysis of the damage. Intergranular oxygen/oxide penetrations occurred either as connected or isolated penetrations deep under the external oxide/substrate interface as far as 10 μm for alloy 600 and only 4 μm for alloy 718. Therefore, assessing this damage precisely is essential to interpret IGSCC susceptibility.

Mots clés: A. Nickel; A. Alloy; C. Intergranular corrosion; C. Internal oxidation; C. Stress corrosion; B. SIMS

Domaines: Matériaux; Micro et nanotechnologies/Microélectronique

Benoît Ter-Ovanessian, Julien Deleume, Jean-Marc Cloué, Eric Andrieu. Quantitative assessment of intergranular damage due to PWR primary water exposure in structural Ni-based alloys. Corrosion Science, 2013, vol. 67, pp. 11-19. ⟨10.1016/j.corsci.2012.09.048⟩. ⟨hal-00864144⟩