Investigation of whisker orientation in SiC whisker-reinforced alumina composites using neutron diffraction

Alumina composites with 10, 20 and 30 vol.% SiC whiskers were fabricated using colloidal processing methods followed by uniaxial hot pressing. Orientation of whiskers was quantified using neutron diffraction methods that allow one to probe the bulk of the composite samples. The results indicate that significant whisker alignment was present even in the green samples and that hot pressing further enhanced this alignment but not to a substantial extent. Although slightly enhanced whisker rotation was observed with increase in whisker content in the alumina matrix, the overall degree of whisker alignment in the final products was not strongly dependent on pH of the slurry and whisker volume fraction.