The effect of chromium and cobalt segregation at dislocations on nickel-based superalloys

Paraskevas Kontis (1) , Zhuangming Li (1) , David Collins (2) , Jonathan Cormier (3) , Dierk Raabe (1) , Baptiste Gault (1)

1 Max-Planck-Institut für Eisenforschung GmbH
2 Department of Materials, University of Oxford;
3 ENDO - ENDOmmagement et durabilité [Institut Pprime]

The segregation of solutes at dislocations in a polycrystalline and a single crystal nickel-based superalloy is studied. Our observations confirm the often assumed but yet unproven diffusion along dislocations via pipe diffusion. Direct observation and quantitative, near-atomic scale segregation of chromium and cobalt at dislocations within γ' precipitates and at interfacial dislocations leading to the partial or complete dissolution of γ' precipitates at elevated temperatures is presented. Our results allow us to elucidate the physical mechanism by which pipe diffusion initiates the undesirable dissolution of γ' precipitates.

Mots clés: Pipe diffusion; Rafting; Dissolution; Atom probe tomography; Recrystallisation

Domaines: Mécanique des fluides [physics.class-ph]; Matériaux et structures en mécanique [physics.class-ph]; Acoustique [physics.class-ph]; Automatique / Robotique; Electromagnétisme; Milieux fluides et réactifs; Energie électrique; Thermique [physics.class-ph]; Vibrations [physics.class-ph]; Physique mathématique [math-ph]; Physique Quantique [quant-ph]; Acoustique [physics.class-ph]; Biomécanique [physics.med-ph]; Matériaux; Polymères

Paraskevas Kontis, Zhuangming Li, David Collins, Jonathan Cormier, Dierk Raabe, et al.. The effect of chromium and cobalt segregation at dislocations on nickel-based superalloys. Scripta Materialia, 2018, 145, pp.76-80. ⟨10.1016/j.scriptamat.2017.10.005⟩. ⟨hal-02310939⟩