Fiber/Matrix Interface Properties of Hybrid Ceramic Matrix Composites

Fiber/matrix interface properties and fiber pull-out behavior have a significant influence on the overall mechanical properties of a composite. The properties of the fiber/matrix interface in two ceramic matrix composite material systems were characterized using multiple fiber pull-out testing. The test specimens were double notched across the faces and contain a single row of several fibers partially embedded in the matrix below the notch. After flexurally fatigue pre-cracking the notch, the fibers are simultaneously debonded and pulled from the matrix using conventional tensile loading equipment. The multiple fiber pull-out technique is particularly useful for testing composites with very small and/or weakly bonded fibers. The material systems compared are continuous silicon carbide fiber reinforced cordierite and a hybrid combination of continuous silicon carbide fibers and silicon carbide whiskers in a base matrix of cordierite. The results of this investigation indicate substantial improvements to interfacial shear strength and frictional sliding resistance can be obtained through the addition of whiskers to the matrix