Abstract
The effects of neutron irradiation to 3.5 and 9.5 dpa at 730 C on a 2D plain woven carbon fiber reinforced
polymer derived SiC matrix composite are presented. For both fluences, the irradiation caused in-plane
contraction and trans-plane expansion. Irradiation also caused substantial reduction in composite flexural
strength (54%) and increase in flexural tangent modulus (+85%). The extents of dimensional/
mechanical property changes were greater for the higher fluence irradiated samples. Those changes suggest
the instability of the polymer derived SiC matrix following irradiation. The nature of the mechanical
property changes suggest increased clamping stress between the fiber and the matrix. The composite
property changes are explained in terms of irradiation effects on composite constituents and are compared
with carbon fiber reinforced carbon matrix composite as a reference material.
