Séminaire LGF – Yubin Zhang (DTU, Danemark) – 16 novembre 2023

Yubin Zhang (DTU, Danemark) est en visite dans notre laboratoire. A cette occasion, il délivrera le séminaire suivant.

Intitulé

High-resolution 3D synchrotron X-ray techniques for recrystallization studies

Résumé

After 20 years of development, the current generation synchrotron techniques, such as 3D X-ray Laue micro-diffraction using differential aperture and diffraction contrast tomography, have matured into powerful tools for measuring the crystallographic orientations, morphologies and local lattice strains of grains within bulk samples in full 3D. In this presentation, several well-designed experiments using these techniques to study recrystallization will be presented, including nucleation at hardness indents, formation residual stresses within recrystallizing grains, and growth of several nuclei into a well-characterized deformation matrix. It is shown that with high-resolution (~1µm) mapping of both the deformation matrix and the recrystallized grains, the local heterogeneous nucleation and growth of recrystallized grains can be correlated to the local deformation microstructure. Critical demand of full-field microstructural characterization for recrystallization studies will be emphasized, and new possibilities offered by laboratory 3D X-ray techniques will be briefly discussed.

Biographie

Dr. Yubin Zhang obtained his PhD degree from Tsinghua University in China in 2009 in the field of materials science and engineering. He is currently working at the department of civil and mechanical engineering at Technical University of Denmark as a senior scientist. His research focuses on 3D/4D studies of microstructure and micro-strain/stress evolution during plastic deformation and annealing of metals and alloys using synchrotron X-ray methods. He has over the last 15 years conducted more than 40 synchrotron experiments at ESRF, DESY and APS. Recently he has also involved in developing laboratory X-ray methods for non-destructive 3D characterization.  He has published more than 80 journal articles and has an H-index of 25.