4D Micromechanical investigation of high cycle fatigue mechanisms at intragranular scale in a polycrystalline nickel superalloy.

This research aims to correlate crack and microstructure data under fatigue loading by characterizing cyclic strain localization during crack nucleation and early propagation. It builds on the ma6296 experiment (November 2024, ESRF, ID11) and is part of the ANR-JCJC MINIFAT-4D project, which investigates the interaction between microstructure, plasticity, and fatigue damage using in-situ 3D characterization and micromechanical modeling. Experiments will be conducted on Inconel 718 using the NANOX test rig, designed for high-cycle fatigue testing at ID11. Data will be obtained primarily through in-situ scanning X-ray diffraction (s3DXRD), along with diffraction and phase contrast tomography (DCT and PCT). The study aims to enhance understanding of fatigue crack nucleation and early propagation mechanisms by correlating microstructure, crack position, and intragranular gradients of elastic deformation or crystalline rotations.