A method to braid three-dimensionally has been investigated in order to hybridize carbon and Kevlar multifilament yarns symmetrically and uniformly. The tensile properties and impact properties of three-dimensional (3-D) hybrid composites have been examined and compared with those of two-dimensional (2-D) hybrid composites. The tensile strength of the 3-D composite deteriorated slightly compared with the rule of mixture. The impact strength, the rupture energy, and the rupture displacement of the 3-D braided hybrid composites were improved considerably due to the excellent impact properties and 3-D structure of Kevler yarns. The impact properties of 2-D laminated hybrid composites have not been enhanced because of weak inter laminar bonding strength.
