Effects of Thermal Shock Cycling on Mechanical and Thermal Properties of Carbon/Basalt Fiber-Reinforced Intraply Hybrid Composites

In this study, the effect of thermal cycling on the mechanical and thermal properties of carbon/basalt fiber-reinforced polymer (CBFRP) composites is investigated. Carbon and basalt fibers are woven in Twill 2/2 pattern in the structure of intraply hybrid composite and fabricated by vacuum-assisted resin infusion molding method. Fabricated composite samples were exposed to 20, 40, 60, and 80 cycles between − 40 and + 120 °C. To evaluate the effect of thermal cycling on the mechanical and thermal properties of composites, tensile, bending, short beam shear and dynamic mechanic analysis tests were carried out. The extracted results such as tensile modulus and strength, flexural modulus and strength, interlaminar shear strength, storage modulus, loss factors and glass transition temperature of RT and samples that were exposed to different number of thermal cycles were compared with each other. It is concluded that increasing the cycle numbers in the beginning of thermal cycling leads to improvement of the mechanical properties of composites. This phenomenon occurs due to the post-curing in the structure of epoxy and enhancement of cross-links at the interface of the fibers and matrix. Increasing the cycle numbers leads to mismatch in the interface of the composite due to different coefficients of thermal expansion between the composite components and emergence of cracks and delamination in the structure of the composite that causes reduction in the mechanical and viscoelastic properties of the CBFRP composites. According to scanning electron microscopy, the fiber pullout, bundle breakage, fiber buckling, debonding and delamination were the most important failure modes in the mechanical tests.