Decorrelated movements of Shockley partial dislocations in the γ phase channels of nickel-based superalloys at intermediate temperature

Sonia Raujol (1) , Mustafa Benyoucef (2) , Didier Locq (3) , Pierre Caron (3) , Florence Pettinari-Sturmel (1) , Nicole Clément (1) , Armand Coujou (1)

1 CEMES - Centre d'élaboration de matériaux et d'études structurales
2 FSTG - Faculté des Sciences et Techniques Marrakech
3 ONERA - The French Aerospace Lab [Châtillon]

In nickel-based superalloys with high volume fraction of γ ' precipitates, dislocations have to experience high curvatures in order to enter narrow channels by glide in the {111} planes of the f.c.c. 冏 matrix. Observation of in situ dynamic sequences performed in a Transmission Electron Microscope on several industrial superalloys have shown the occurrence of decorrelated movements of Shockley partial dislocations, originating from perfect dislocation dissociation. By evaluating the effective stress acting on each one of these partial dislocations, as well as their respective flexibility, the possible occurrence of such movements for some particular dislocation characters and channel widths is accounted for. These movements can play an important role in the creep behaviour of these materials in the low deformation rate regime.

Mots clés: Physical Sciences

Sonia Raujol, Mustafa Benyoucef, Didier Locq, Pierre Caron, Florence Pettinari-Sturmel, et al.. Decorrelated movements of Shockley partial dislocations in the γ phase channels of nickel-based superalloys at intermediate temperature. Philosophical Magazine, 2006, 86 (09), pp.1189-1200. ⟨10.1080/14786430500254685⟩. ⟨hal-00513572⟩