Shaping process for advancerd ceramic materials by ice templating (freeze casting)

Abstract

Ice templating of colloidal suspension is gaining interest in material science because it offers the possibility to shape advanced materials, in particular porous ceramics. Recent investigations on this process show that a correlation between the morphology of the frozen suspension and the velocity of the freezing front do exist. The dynamics of the freezing front of a colloidal suspension of alumina is investigated in this study by experimental tests, finite element analysis, and analytical calculations. The experimental tests are carried out by in situ X-ray radiography (dynamics of the freezing front) and tomography (morphology of the frozen suspension). The finite element model is a continuous properties model; it is used for investigating the dynamics and the shape of the freezing front. The analytical model is based on the two-phase Stefan problem. We propose a solution for the dynamics of the solidification front based on the calculation of the diffusivity as a function of the particle fraction and local temperature.

Publications

"Dynamics of the Freezing Front During the Solidification of a Colloidal Alumina Aqueous Suspension: In Situ X-Ray Radiography, Tomography, and Modeling."
A. Bareggi, E. Maire E., A. Lasalle, S. Deville, Journal of American Ceramic Society, vol. 94, issue 10, pp.3570-3578, October 2011

Damage in dual phase steels and its constituents studied by X-ray tomography

Abstract

Damage in a dual phase steel was measured using in situ high-resolution X-ray absorption tomography. A comparison with the behavior of its two constituents ferrite and martensite, taken separately, was also achieved in the present work. The method was particularly useful for analyzing the respective contribution of nucleation and growth of voids in the studied materials. Quantitative analysis of the damage events was carried out on a same 3D region inside the reconstructed volumes at different deformation steps for different samples cut from the three kinds of materials. Void nucleation and growth model, based on local stress triaxiality, show a good agreement with the experimental data.

Publications

"Damage in dual phase steels and its constituents studied by X-ray tomography."
A. Bareggi, E. Maire, O.Bouaziz, M.Di Michiel International Journal of Fracture 04/2012; 174(2):217-227. DOI:10.1007/s10704-012-9692-4

"Analysis of Damage in Metallic Materials by X-ray Tomography."
A. Bareggi, E. Maire, M.Giton, O. Bouaziz, M. Dimichiel Proceeding (CD) of 12 International Conference on Fracture, July 2009, Ottawa, Canada