Deformation features of a nickel-base superalloy single crystal during compression creep

The microstructure evolution of a single crystal nickel-base superalloy with [0 0 1] orientation during compressive creep at 1040 degreesC has been investigated by means of the observation of transmission electron microscopy. Results show that the cuboidal gamma' phase in the alloy is transformed into the strip-like rafted structure along the direction parallel to [0 0 1] stress axis during compressive creep. During the primary creep, the deformation feature of the alloy is the 1/2 dislocations activated in the gamma matrix. After crept for 50 h, the strip-like rafted gamma' (Ni3Al) phase in alloy is sheared by the super-dislocations which may be dissociated into the 1/3 super-Shockley dislocations. The SISF formed from the dissociation of the [1 0 (1) over bar] super-dislocation is enclosed by the partials loops. One of the reason resulting in a smaller strain value of the alloy during compressive creep is the Giameis locks made from a combination of the partials loops and SISF which hinder the continuous expansion of the original [1 0 (1) over bar] super-dislocation. (C) 2004 Elsevier B.V. All rights reserved.