Effects of the Cr-depletion on the stress state of the sublayer of ni-base alloys oxidized in high temperature water

Benoît Ter-Ovanessian (1) , Eric Andrieu (2) , Dominique Poquillon (2) , Alexandre Freulon (2) , Jean-Marc Cloué (2)

1 MATEIS - Matériaux, ingénierie et science [Villeurbanne]
2 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux

The exposure in high-temperature water (300–360°C) of Alloy 600 is known to induce not only generalized corrosion, but also degradation at the underlying base metal such as intergranular penetrations of oxygen and\or oxides and Cr-depletion. Possible consequences of Cr-depletion are the creation of local stresses in the underlying metal due to local variations of the lattice parameter, and the formation of physicals properties gradient, like the elastic modulus or thermal expansion coefficient. In order to assess the effects caused by the Cr-depletion on an exposed Alloy 600, finite element (FE) calculations and physical properties characterisations on synthetic alloys with a chemical composition representative of different Cr-depleted layers, were performed. The levels of the calculated stresses were then discussed regarding to the other features of oxidation involved in the high temperature water stress-corrosion cracking mechanism.

Mots clés: Cr-depletion; High temperature water; Nickel alloy; SCC

Domaines: Matériaux

Benoît Ter-Ovanessian, Eric Andrieu, Dominique Poquillon, Alexandre Freulon, Jean-Marc Cloué. Effects of the Cr-depletion on the stress state of the sublayer of ni-base alloys oxidized in high temperature water. Oxidation of Metals, 2013, 79 (1-2), pp.73-80. ⟨10.1007/s11085-012-9327-1⟩. ⟨hal-01755504⟩