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Nickel base superalloys

Ageing elementary mechanisms of Nickel base superalloys

Staff: Armand Coujou, Joël Douin, Lise Durand, Florence Pettinari-Sturmel
Ph.D. students & Postdocs: Muriel Hantcherli

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Deformation micromechanism in confined plasticity: observation of the uncorrelated movement of a dislocation during an in situ tensile test, compared with the modelling (dotted line).

The nickel-based superalloys are two-phase materials. The hardening precipitates γ’ (L12 ordered of Ni3Al type) are embedded in the short range ordered γ phase.

These alloys are used in the warmest part of the turboreactors. They can be classified in two parts: the polycristalline superalloys for turbine disc application and the single crystals for turbine blade application.

Because they are used in extreme temperatures and stress conditions, the superalloys age. This ageing is at the origin of important morphological modifications, which strongly affect the stability and the security of the air transport.


Then, the elementary mechanisms responsible for these evolutions need to be understood, by combining a nano and micro scale approach.

In addition, the study and the modelling of the mechanical behavior at different scales: micro, meso and macroscopic, are essential as well as the relationship between these observation scales.


Research Topic:

  • Elementary mechanisms and destabilization of the rafting in relation with the order quality in single crystal nickel base superalloys.
  • Ageing mechanisms and associated deformation micro-mechanisms in bimodal precipitation superalloys for disc application.
  • Modelling the mechanical behavior of nickel base superalloys by finite element method (FEM).


Selected publications

  • F. PETTINARI-STURMEL, S. RAUJOL, J. DOUIN AND A. COUJOU The role of the γ/γ’ interfaces in the creep behavior of the NR3 superalloy INSTN 3M (sous presse Materials Science & Engineering A)
  • DURAND, L., M.MASSAOUDI, M.CABIÉ, AND A. PONCHET, Mechanical behaviour of a two-phase material from the behaviour of its components: Interface modeling by finite element method, Materials and Design, 2008, 29, p.1609-1615
  • N. CLÉMENT, M. BENYOUCEF, M. LEGROS, P. CARON ET A. COUJOU "In situ Deformation at 850°C of Standard and rafted Microstructures of Nickel Base Superalloys", Materials Science Forum, 2006, Vol. 509 pp.57-72
  • MASSAOUDI, M. AND L. DURAND, Modelling by FEM the effect of the morphological modifications of the superalloys γ/γ’, Journal of the Mechanical Behavior of Materials, 2006. 17 (2): p.121-135.
  • F. PETTINARI-STURMEL, J. DOUIN, A. COUJOU, N. CLÉMENT Characterisation of short-range order using dislocations" Z. Metallkd., 2006, 97 3
  • RAUJOL S., M. BENYOUCEF, N. CLEMENT and A. COUJOU, Decorrelated movements of Shockley partial dislocations in the γ channels of Nickel- base superalloys at intermediate temperature. Phil. Mag., 2006, 86 (9), 1189 – 1200
  • S. RAUJOL, F. PETTINARI-STURMEL, J. DOUIN, N. CLÉMENT, A. COUJOU, D. LOCQ, P. CARON, A new TEM method for the characterization of the tertiary γ’ nano-precipitates in a PM disk superalloy. Influence of ageing Phil. Mag., 2006, 86, 4507 – 4518
  • DURAND, L., M. MASSAOUDI, AND B. LAVELLE, X-Rays diffraction study of elastic strains for modelling γ/γ’ two-phase behavior. Materials & Design, 2005. 26(5) p. 402-409.
  • F. PETTINARI-STURMEL, A. COUJOU AND N. CLÉMENT The fluctuation of short range order evidenced by mobile dislocations in the γ-phase of a nickel-base superalloy Materials Science and Engineering A, 2005, 400-401 114-117
  • DURAND, L. AND M.MASSAOUDI, Recent developments on the finite element method used in the analysis of the behaviour of materials. Recent Res. Devel. Mat. Sci. Engg, 2004. 3: p. 21-38.
  • MASSAOUDI, M., L. DURAND, AND A. ALTIBELLI, Finite Elements Modelling of the γ/γ’ Two –Phase Viscoplastic Behaviou,. Journal of the Mechanical Behavior of Materials., 2004. 15(4-5): p. 254 - 277.
  • F. PETTINARI-STURMEL, G. SAADA, J. DOUIN, A. COUJOU, N. CLÉMENT. Quantitative analysis of dislocation pile ups in thin foils compared to bulk, Materials Science and Engineering A, 2004, 387 – 389, 109 – 114