Some Results from X-Ray Computed Tomography Applied to Metal Matrix Composites

This study presents computed tomography (CT) results from a medical scanner carried out on metal matrix composite materials obtained by a casting process. In order to test the capabilities of the CT technique to study the flaws in the sample, few precautions have been taken during the manufacturing process, resulting in composite ingots with many flaws (porosity, segregation, etc.). The mold was modified to obtain a concentration of particles at the bottom of the ingot. CT images and scanning electronic microscopy images were taken at the same slice surface and show good agreement in the distribution of particles and porosity. The spatial resolution of the medical scanner (12 pairs of lines/cm) lets us distinguish between, at the mesoscopic scale, heterogeneous distribution of particles and porosity, but not individual flaws.