High-temperature deformation of cordierite glass-ceramic/SiC platelet composites

Composites based on barium-containing cordierite glass-ceramic matrices reinforced with 20 and 30 vol% SiC platelets were fabricated by hot-pressing. The ceramed specimens were tested in compression at 1000, 1200 and 1300 degrees C in air, parallel and perpendicular to the hot-pressing direction. Compressive fracture stresses up to 460 MPa were recorded at 1000 degrees C. Lower stresses were observed at 1200 and 1300 degrees C. The compressive stress decreased with increase in the SIC platelet content and with the compressive direction being parallel to the hot-pressing axis. The mechanical behaviour at high temperatures was related to the presence of a residual glassy phase within the cordierite matrix, as well as to the mode of the crack nucleation within the composites.