THERMAL-EXPANSION BEHAVIOR OF PARTICULATE-FILLED COMPOSITES .2. MULTI-REINFORCING PHASES (HYBRID COMPOSITES)

In part I of this paper, the effect of filler shape on the thermal expansion behavior of a composite with a single reinforcing phase was studied. In this paper emphasis is placed upon the effect of using multi-components as the reinforcement (hybrid composite) on the thermal expansion behavior of a short fiber-composite. The hybrid composite system examined consists of a Kerimid matrix and two kinds of reinforcement: Al2O3 short fibers and Si3N4 whiskers. The former reinforcement represents a large-sized fiber, while the latter plays the role of a small-sized fiber. This leads to two advantages: (1) an increase in the volume fraction of the reinforcement, thus resulting in a lower coefficient of thermal expansion (CTE) of the composite, and (2) control of the orientation of these fibers, thus leading to improvement in the thermal expansion behavior of the composite along the thickness direction.