Effect of saltwater on the mechanical properties of basalt/carbon/glass-epoxy hybrid composites

The impact of environmental conditions on the mechanical properties of composites is critical for various industries, particularly marine. The paper examines the effect of saltwater conditions on the mechanical properties of basalt, carbon, and glass fibers/epoxy hybrid composites. The composite samples were manufactured using Vacuum Assisted Resin Transfer Molding (VARTM) and then immersed in saltwater solution before tests. The tests were performed using Instron 8801 with 100 kilonewtons (kN) capacity. The environmental effects on the mechanical properties were supported by the Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) analysis of the water. The ICP-OES analysis result shows a transfer of ions from the fiber to the saltwater solution. As a result, the mass gain of all the samples increases with the conditioning period, while the tensile and flexural properties show degradation. Moreover, the hybrid composites show a gradual failure mode compared with non-hybrid composites. In addition, the failure modes and morphological analysis of the failed test samples were presented. Delamination, explosive failure, and fiber breakage characterize the tensile failure mode of basalt/epoxy (BE) and its hybrids. However, the glass/epoxy (GE) and carbon/epoxy (CE) show fractures in two or three sections. In addition, compressive failure, tensile failure, shear failures, delamination, and fiber breakage were detected in the flexural samples.