The role of slip transfer at grain boundaries in the propagation of microstructurally short fatigue cracks in Ni-based superalloys

M. Jiménez , Wolfgang Ludwig (1) , D González , J.M. M Molina-Aldareguia

1 ESRF - European Synchrotron Radiation Facility

Crack initiation and propagation under high-cycle fatigue conditions have been investigated for a polycrystalline Ni-based superalloy by in-situ synchrotron assisted diffraction and phase contrast tomography. The cracks nucleated along the longest coherent twin boundaries pre-existing on the specimen surface, that were well oriented for slip and that presented a large elastic incompatibility across them. Moreover, the propagation of microstructurally short cracks was found to be determined by the easy slip transfer paths across the pre-existing grain boundaries. This information can only be obtained by characterization techniques like the ones presented here that provide the full set of 3D microstructural information.

Mots clés: X-ray synchrotron radiation; Grain boundary; High Cycle Fatigue; Superalloy; Microstructurally short crack propagation

Domaines: Matériaux

M. Jiménez, Wolfgang Ludwig, D González, J.M. M Molina-Aldareguia. The role of slip transfer at grain boundaries in the propagation of microstructurally short fatigue cracks in Ni-based superalloys. Scripta Materialia, 2019, 162, pp.261-265. ⟨10.1016/j.scriptamat.2018.11.008⟩. ⟨hal-02404396⟩