Gamma radiation-induced degradation of mechanical properties in Carbon/Kevlar hybrid epoxy composites for aerospace applications

Abstract

This study examines the impact of gamma radiation on the mechanical characteristics of carbon/Kevlar hybrid epoxy composites used in aerospace applications. Composites consisting of carbon (CCCC), Kevlar (KKKK), and hybrid (CKCK) fabrics with varied stacking sequences were produced using a hand lay-up technique. These composites were then exposed to different dosages of gamma radiation (1 kGy, 3 kGy, and 5 kGy ). A thorough mechanical analysis was conducted, encompassing tests for tensile strength, flexural strength, impact resistance, interlaminar shear strength (ILSS), hardness, and water absorption. The carbon composite that was not exposed to radiation demonstrated the maximum tensile strength, measuring 246.28 MPa. Additionally, it exhibited a flexural strength of 787.72 MPa and an interlaminar shear strength (ILSS) of 9.75 MPa. After being exposed to a radiation dose of 5 kGy, the values decreased to 215.36 MPa, 578.49 MPa, and 8.71 MPa, respectively. Among the materials that were examined, the hybrid composite had the highest impact strength of 0.0537 J/mm2. The results of dynamic mechanical analysis showed a reduction in the storage modulus from 11762.1 MPa to 10338.7 MPa, and a decrease in the glass transition temperature from 113.05 °C to 107.7 °C following exposure to 5 kGy of radiation. The scanning electron microscopy (SEM) analysis of fractured surfaces revealed a transition from a ductile to a brittle fracture behaviour as the radiation doses increased.