X-ray microtomography of damage in particle-reinforced metal matrix composites

The damage which occurs on plastic straining of silicon carbide particle-reinforced aluminium alloys has been characterised using x-ray rnicrotomography. The technique is used to provide density measurements as a function of strain in addition to imaging the interna1 structure with a resolution of ≈15µm. This allows a much more accurate determination of microstructural damage in terms of void growth than is available from measurements of density using buoyancy methods or from elastic modulus decrease. These data can be combined with acoustic emission measurements during straining to allow damage nucleation and growth contributions to be separated