抄録
The effect of the fiber-matrix chemical reaction which occurs during thermal exposure on the tensile strength of a SiC/Ti-6Al-4V composite was studied. The tensile strength of the composite decreased with an increase in the fiber-matrix reaction zone thickness. Especially, a drastic degradation occurred when the reaction zone thickness exceeded 1μm. The strength of the fibers extracted from the composite also decreased as the fiber-matrix reaction proceeded. This degradation in the fiber strength was caused by the surface roughness of the fiber due to the fiber-matrix reaction. The strength of the composite was approximately identical with the value estimated from the ROM (Rule of Mixture) using the strengths of the matrix and the extracted fibers.
It was assumed from the observation of fracture surfaces of the composite and AE analysis during the tensile test that a fiber-matrix reaction zone debonding occurred before failure of the fiber. Therefore, it is concluded that the degradation in strength of the composite by thermal exposure can be attributed not to a notch effect of cracking in the reaction zone, but to the decrease in strength of the fiber itself.
