Rafting microstructure during creep of the MC2 nickel-based superalloy at very high temperature

Fabienne Touratier (1) , Eric Andrieu (1) , Dominique Poquillon (1) , Bernard Viguier (1)

1 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux

Directional coarsening of the single-crystalline nickel-based superalloy MC2 has been investigated by means of tensile creep tests at 1100 ◦C. Two specific specimen geometries were designed in order to generate a variety of stress and strain states. Different coarsening microstructures are observed: N- and P-type classical rafting but also coarsening oriented 45◦ away from the load axis. The comparison of microstructure maps with the local mechanical state evaluated by finite element calculations shows that the 45◦ directional coarsening appears in case of very high cumulated strain values (above 10%), independent of the stress sign. Transmission electron microscopy investigations showthat the dislocation microstructure is similar in both N-type and 45◦ coarsened areas.

Mots clés: Single crystal nickel-based superalloy; High temperature creep test; Rafting; Stress and strain states

Domaines: Matériaux

Fabienne Touratier, Eric Andrieu, Dominique Poquillon, Bernard Viguier. Rafting microstructure during creep of the MC2 nickel-based superalloy at very high temperature. Materials Science and Engineering: A, 2009, 510-511, pp.244-249. ⟨10.1016/j.msea.2008.04.100⟩. ⟨hal-03571926⟩