Dislocation Structures in the Gamma Prime-Phase of CMSX-4 and TMS75 after Degradation under Service Conditions

Thomas Link; Alexander Epishin; Nils Nawrath; Catrina Michel; Mohamed Nazmy

doi:10.4028/www.scientific.net/AMR.278.25

Paper Titles

Mechanical Properties of the Ternary L1₂ Compound Co₃(Al,W) in Single and Polycrystalline Forms
p.1

Dislocation Mechanisms during High Temperature Creep Experiments on MC2 Alloy
p.7

Evolution of Raft Structure during Creep Deformation of the Ni-Based Single-Crystal Superalloy TMS-138
p.19

Dislocation Structures in the Gamma Prime-Phase of CMSX-4 and TMS75 after Degradation under Service Conditions
p.25

Dissolution of Fine γ’ Precipitates of MC2 Ni-Based Single-Crystal Superalloy in Creep-Fatigue Regime
p.31

Diffraction Profile, Strain Distribution and Dislocation Densities during Stage II Creep of a Superalloy
p.37

In Situ Investigation with Neutrons on the Evolution of γ ' Precipitates at High Temperatures in a Single Crystal Ni-Base Superalloy
p.42

In Situ Measurement of Internal Stresses and Strain Rates by High Energy X-Ray Diffraction during High Temperature Mechanical Testing
p.48

HomeAdvanced Materials ResearchAdvanced Materials Research Vol. 278Dislocation Structures in the Gamma Prime-Phase of...

Dislocation Structures in the Gamma Prime-Phase of CMSX-4 and TMS75 after Degradation under Service Conditions

Abstract:

The single crystal superalloys CMSX-4 and TMS75 were tested for very long times at high temperatures in laboratory creep tests and in service. The microstructure was investigated in TEM and SEM. It was found, that the ’-phase is cut at stresses much below the threshold given in literature. Cutting takes place by <110> screw dislocations. These mobile dislocations can be locked locally by a Giamei-lock. Thus a stacking fault dipole forms between the locked segment and the preceding ones. The dipole consists of two supershockley dislocations with 30° character, which are also stabilized by Giamei locks. The dipole formation is analyzed and discussed in detail.

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