From random chopped to oriented continuous SiC fibers-ZrB_2 composites

摘要

ZrB_2-continuous SiC fiber composites were prepared by vacuum-bag infiltration and hot pressing, using homemade 1D fabric preforms of Tyranno SA3 SiC fibers. Sintering behavior and microstructural features such as secondary phases and matrix/fiber interface were compared to those of chopped SiC fibers-reinforced composites. The infiltration process allowed the overall fiber content to be increased up to 40 vol%, because of the ordered arrangement of fibers. When the fiber preforms were properly infiltrated, the composites were nearly fully dense and the densification mechanisms were the same as those of unreinforced matrices. Different from composites containing short discontinuous fibers, the degree of chemical interaction at the fiber/matrix interface was very limited and this resulted in an easier pull out in the fractured surfaces, even in absence of fiber protective coating.