PhD student in 4D diffraction imaging of grain growth in metals using pink-beam topotomography

As a PhD student at the ESRF, you will investigate grain growth in polycrystalline metals by 4D (3D + time) synchrotron diffraction imaging within the project 4DGG, funded by the French National Research Agency (ANR) and coordinated by the ESRF in partnership with the MATEIS laboratory at INSA Lyon (Wolfgang Ludwig) and CEMEF at Mines Paris, PSL University (Marc Bernacki). Classical models treat grain growth as curvature-driven boundary migration, yet 3D studies show that boundary velocity and curvature are often poorly correlated, pointing to contributions from elastic strain and dislocation substructures that remain to be measured directly in 3D during growth. You will use pink-beam topotomography, developed within the project at beamline ID03, in which rotating the sample about the diffraction vector of a selected grain keeps it in diffraction condition and enables time-resolved 3D imaging of grains and their boundaries during in situ annealing. Combined with dark-field X-ray microscopy (DFXM), 3DXRD and diffraction contrast tomography (DCT), these measurements will follow normal and abnormal grain growth in aluminium, iron and nickel, and provide quantitative input for full-field grain growth models. You will be enrolled in the École Doctorale de Physique at Université Grenoble Alpes (UGA) on a 3-year contract, with Can Yildirim (ESRF) as main supervisor.

Your responsibilities include:

·         Preparing polycrystalline aluminium, iron and nickel samples and selecting target grains by 3DXRD and DCT.

·         Designing and performing in situ high-temperature grain growth experiments at ID03 combining pink-beam topotomography, DFXM and 3DXRD/DCT.

·         Reconstructing and analysing the 4D datasets to quantify grain boundary velocity, curvature, misorientation and elastic strain, in close collaboration with INSA Lyon on topotomographic reconstruction.

·         Providing experimental input to the full-field simulations of grain growth performed at CEMEF, and comparing measured and simulated microstructure evolution.

Publishing the results, presenting at international conferences, and writing and defending a doctoral thesis at UGA.