Mechanical properties and structure of a new commercial SiC-type fibre (Tyranno)

An initial evaluation of a new titanium-doped polymer-pyrolysis SiC fibre, Tyranno showed a narrow distribution of diameters with a mean of 8.5 mu m; average tensile strength S@u- greater than or equal to 3 GPa, nearly independent of gauge length in the 1 to 4 cm range; Weibull parameter m approximately equals 7.3; and mean Young's modulus E@u- approximately equals 170 GPa. Heat treatment at 1300 to 1350 degree C in N sub(2) appreciably reduced S, m and E; and X-ray diffraction showed that significant crystallite growth as well as some Si sub(3)N sub(4) formation had occurred. Tyranno fibre properties are compared with those of the well-known Nicalon SiC fibre.