Mechanical properties of hybrid composites reinforced by carbon fiber and high-strength and high-modulus polyimide fiber

High-strength and high-modulus polyimide fiber is a kind of high-performance organic fiber rapidly developing in recent years. Taking advantage of its high strength and toughness and being combined with carbon fiber, it is expected to make a balance between stiffness and toughness, so as to afford a kind of structural composite with high strength and toughness. In this study, a series of hybrid fiber reinforced composites were prepared with high-strength and high-modulus PI fiber and carbon fiber as reinforcements. The effects of stacking sequence and hybrid ratio on the tensile, compressive and flexural properties and failure modes of the composites were systematically investigated. Experimental results showed that tensile, compressive and flexural properties of the hybrid composites were markedly improved compared with polyimide fiber composite, while failure strain and failure energy were superior to those of the carbon fiber composites. The flexural properties were largely affected by the stacking sequence. Hybrid composites with carbon fiber as the compressive side showed higher flexural strength, while the ones with carbon fiber as both compressive side and tensile side had higher flexural modulus.