Dislocation microstructure in a single-crystal nickel-based superalloy after tensile testing at 823 K in the [001] direction
Authors:
- 1 June 1992
- journal article
- research article
- Published by Taylor & Francis in Philosophical Magazine A
- Vol. 65 (6) , 1353-1368
Abstract
In the two phase Ni-based superalloy SRR 99, deformation mechanisms are analysed after tensile testing at 823 K in the [001] direction. Deformation starts by octahedral glide of screw dislocations in the matrix and creation of long 60° segments in the γ-γ interfaces. After 1% strain, γ' precipitates are cut by pairs of 60° dislocations which create long screw superdislocation dipoles. Dipole annihilation causes constant dislocation density in the γ' phase. Antiphase-boundary energies in the ordered phase are anisotropic. Concerning dislocation pair configurations the criterion for cross-slip developed by Paidar, Pope and Vitek and by Yoo is modified. The relations between microstructure and mechanical behaviour are discussed.Keywords
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