Finite element simulations of the deformation of fused-cast refractories based on X-ray computed tomography

This work consists in building a 3D numerical model of the microstructure of a fused-cast refractory (two-phase material). Creep tests at temperatures as high as 1400 degrees C reveal a major influence of the morphology of the phases on the material behavior. A possible 3D connectivity of the zirconia grains, related to the fabrication process, may explain the observed high creep resistance. In order to have a realistic representation of the microstructure, 3D pictures have been obtained using X-ray microtomography at the European Synchrotron Radiation Facility in Grenoble (ESRF). Volumetric tetrahedral grids are generated from the exploitation of these pictures using available meshing techniques. Finite elements calculations are performed to study the influence of the glassy phase content on the stiffness of the material. Simulations are compared with experiments. In particular the notions of geometrical and mechanical percolation are investigated numerically. High elastic stiffness is predicted, even for large amorphous phase contents. A percolation threshold is observed for the geometry of the hard phase (zirconia phase) but not for the Young's modulus. (c) 2006 Elsevier B.V. All rights reserved.