Interface Properties for Ceramic Composites from a Single-Fiber Pull-Out Test

Abstract

AbstractAn experimental approach has been developed using a single-fiber pullout test to measure intrinsic interface properties for ceramic composites. The properties are determined from a pull-out, force-displacement curve, which is directly related to reinforcement toughening via fiber/matrix debonding and frictional pull-out. They were evaluated for a model composite system of continuous SiC fibers with various surface treatments in a borosilicate glass matrix. For the processing conditions used, the interface fracture toughness and the interface frictional shear resistance were found to be 1.0 ± 0.5 J/m2 and 3.3 ± 0.6 MPa, respectively, for as-received fibers. Experiments conducted with long embedded fiber lengths allowed the shear resistance to be deconvolved into an interface friction coefficient of 0.05 ± 0.01 and an initial fiber-clamping pressure of 65 ± 6 MPa. Nitric acidwashed fibers gave an increased interface toughness of 3.6 ± 0.1 J/m2 and friction coefficient of 0.08 ± 0.02, but nearly the same initial clamping pressure, 72 ± 12 MPa. Calculations of the clamping pressure from the fiber/matrix thermal expansion mismatch and from stress birefringence measurements in the glass were in general agreement with this value.