25 juil
25/07/2019 09:00

Sciences & Société

Soutenance de thèse : Ning DANG

Soutenance d'une thèse de doctorat de l’Université de Lyon en cotutelle internationale entre l’Université de Beihang (Pékin, Chine) et l’INSA Lyon

3D Visualization of Microstructure and damage evolution in light metals

Doctorant : Ning DANG

Laboratoire INSA : MATEIS
Ecole doctorale : ED34 : Matériaux de Lyon

Titanium and its alloys, which have integrated properties including low density, high specific strength and excellent corrosion resistance, are “workhorses” in the field of modern industries. In recent years, with the development of industrial technologies, we have stricter requirement on the properties of components made by titanium alloys in severe environment. How to explore further potential properties in titanium alloys? Such question has attracted researchers’ eyes. Therefore, in order to reveal the micro- mechanism of damage and fracture for titanium alloys intensively, it is quite necessary to enhance our knowledge on the microstructure characteristics and damage evolution features, particularly on the interplay between microstructure characteristics and voids development. In this thesis, aiming at the variation of microstructure morphologies during damage development, based on synchrotron X-ray computed tomography(X-ray CT) approach, an integrated methodology containing in situ tensile experiment and CP (Crystal Plasticity) simulation was implemented to focus on the microstructure morphologies and void nucleation/propagation behavior of Ti-6Al-4V(TA6V) alloy during damage evolution. Besides, with the help of realistic microstructure-based RVE (Representative Volume Element) modeling and subsequent deforming simulation, combining with post mortem by SEM/EBSD, we have revealed the mechanism for damage development by deeply analyzing the fracture features. Finally, the correlation between microstructure features and damage evolution was discussed on the basis of results from simulations and experiments.