Effects of Reinforcement Surface Morphology on Toughening of Brittle-Matrix Composites

The mechanical properties of brittle-matrix composites critically depend upon the nature of the reinforcement/matrix interface. Recent theoretical and experimental work has shown that the morphology of the reinforcement surface can play a dominant role in determining the toughening behavior in these materials. In this work, the role of reinforcement surface roughness is examined both analytically and experimentally. Measurements of the debonding and frictional sliding of rough fibers in glass matrices, obtained using a modified fiber pullout technique, show a significant dependence on fiber surface roughness. The effects of surface roughness are explored further by measuring systematic changes in the fiber sliding behavior with controlled fiber coatings. The available analytical models of rough fiber sliding are examined to interpret the experimental results