A new configuration for a super-dislocation in the γ’ phase of a fourth-generation single-crystal TMS38 superalloy was found after creep rupture in a [001] tensile test at 1150C and 137MPa. The segments of the super-dislocation lay in 4 directions: [110], [1¯10], [100] and [010], strictly on a (001) plane with a Burgers vector of [001]. This super-dislocation was pure edge in character and did not dissociate into super-partials. Microstructural evidence showed that this kind of super-dislocation was formed by the combination of 2 interfacial dislocations having differing Burgers vectors:

½[011] + ½[0¯11]  [001]

New Configuration of a [001] Super-dislocation Formed during High-Temperature Creep in the γ' Phase of a Single-Crystal Superalloy TMS-138. J.X.Zhang, H.Harada, Y.Koizumi: Journal of Materials Research, 2006, 21[3], 647-54