  The mechanical behavior of a Mo-TiC30 vol.% ceramic-metal composite was
investigated over a large temperature range (25^{\circ}C to 700^{\circ}C).
High-energy X-ray tomography was used to reveal the percolation of the hard
titanium carbide phase through the composite. Using a polycrystal approach for
a two-phase material, finite element simulations were performed on a real 3D
aggregate of the material. The 3D microstructure, used as starting
configuration for the predictions, was obtained by serial-sectioning in a dual
beam Focused Ion Beam (FIB)-Scanning Electron Microscope (SEM) coupled to an
Electron Back Scattering Diffraction system (3D EBSD, EBSD tomography). The 3D
aggregate consists of a molybdenum matrix and a percolating TiC skeleton. As
most BCC metals, the molybdenum matrix phase is characterized by a change in
the plasticity mechanisms with temperature. We used a polycrystal model for the
BCC material, which was extended to two phases (TiC and Mo). The model
parameters of the matrix were determined from experiments on pure molydenum.
For all temperatures investigated, the TiC particles were considered as
brittle. Gradual damage of the TiC particles was treated, based on an
accumulative failure law that is approximated by an evolution of the apparent
particle elastic stiffness. The model enabled us to determine the evolution of
the local mechanical fields with deformation and temperature. We showed that a
3D aggregate representing the actual microstructure of the composite is
required to understand the local and global mechanical properties of the
studied composite.
