Transmission electron microscopy of dislocation dissociations and stacking faults in γ′-hardened nickel-base superalloys

Abstract

The dislocation structures of compression tested single crystals of the commercial γ'-hardened nickel-base superalloy NIMONIC 105 and of similar experimental alloys have been studied by transmission electron microscopy. If the radius and the volume fraction of the γ'-precipitates exceed 20nm and 0.31, respectively, wide extrinsic and intrinsic stacking faults were found. They were bounded by Shockley partial dislocations. The dislocation reactions and microstructural conditions leading to the formation of the stacking faults are analysed.