Mj. Blissett et al., Flexural mechanical properties of thermally treated unidirectional and cross-ply Nicalon-reinforced calcium aluminosilicate composites, J MATER SCI, 33(16), 1998, pp. 4181-4190
Long, square cross-section samples of a unidirectional and a cross-ply [0/9
0](3s) silicon carbide (Nicalon) fibre calcium aluminosilicate glass-cerami
c matrix composite have been subjected to a range of thermal treatments. Th
ey were held at temperatures up to 800 degrees C above room temperature for
1, 6 or 24 h then slowly cooled or quenched into water. The thermal cycle
was repeated up to six times for a small number of samples. The effects of
these thermal regimes on Young's modulus, onset of matrix cracking (as asse
ssed by onset of non-linearity in the load-displacement curve) and flexure
strength have been monitored using three-point flexure testing. In very bro
ad terms, where clear trends emerged, the intermediate temperature differen
tials, i.e. 400-650 degrees C, have been found to have the most detrimental
effects on properties, and this has been linked to expected changes in the
carboneous interphase and its subsequent replacement by silica. (C) 1998 K
luwer Academic Publishers.