The Hybrid Model and Mechanical Properties of Hybrid Composites Reinforced with Different Diameter Fibers

By using carbon fiber (CF) as small-diameter fiber, SiC fiber (SiCF) or boron fiber (BF) as large-diameter fiber, the SiCF/CF and BF/CF fiber reinforced epoxy resin hybrid composites have been fabricated and investigated. Through SEM micrograph analysis and fiber volume fraction statistics, the hybrid fiber distribution model of bi-diameter hybrid composites has been developed. Compressive and flexural properties of both hybrid composites were tested, and then the damage characteristics and the fracture mechanism of the two kinds of hybrid composites were studied contrastively. The hybrid effect of BF/CF composites is positive, i.e., the hybrid composites have higher compressive and flexural strengths than CFRP and BFRP. In contrast, the compressive and flexural strengths of SiCF/CF composite are both between those of CFRP and SiCFRP. The simple linear addition rule slowly dominates, obviously. The flexural modulus of the two hybrid materials obeys the rule of mixture.