Investigation of {gamma}/{gamma}{prime} lattice mismatch in the polycrystalline nickel-base superalloy IN738LC: Influence of heat treatment and creep deformation
- Hahn-Meitner-Inst. Berlin GmbH (Germany)
The {gamma}/{gamma}{prime} lattice misfit in the polycrystalline nickel-base superalloy IN738LC has been determined by convergent beam electron diffraction (CBED) technique in a transmission electron microscope (TEM). The influence of heat treatment and creep deformation on the misfit was investigated. The chemical compositions of the {gamma} and {gamma}{prime} phases were analyzed with the help of Energy Dispersive Spectrometry (EDS). The influence of different heat treatments on the {gamma}/{gamma}{prime} misfit can be explained in terms of the dependence of the chemical compositions of {gamma} and {gamma}{prime} phases on the heat treatments. The creep deformation causes a tetragonal distortion in {gamma}{prime} precipitates and leads to considerable changes in the misfit. The tetragonality in {gamma}{prime} phase and the evolution of the misfit during creep process can be understood on the basis of a dislocation model. An estimation of the local internal stress in {gamma}{prime} phase generated by {gamma}/{gamma}{prime} interfacial dislocations formed during creep deformations shows it to be higher than the applied stress.
- OSTI ID:
- 27883
- Journal Information:
- Acta Metallurgica et Materialia, Vol. 43, Issue 2; Other Information: PBD: Feb 1995
- Country of Publication:
- United States
- Language:
- English
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