Investigation of the flexural behavior of aluminum-epoxy-basalt fiber layered composites containing clay particles

In this study, the flexural behavior of aluminum–epoxy–basalt fiber fiber-metal laminates (FMLs) reinforced with surface-modified and unmodified montmorillonite nanoclay was systematically investigated. Basalt-fiber-reinforced epoxy was used as the core layer between two 2024-T3 aluminum sheets, and nanoclay was incorporated into the epoxy matrix at 0, 1, 3, and 5 wt.% using combined mechanical and ultrasonic dispersion. Three-point bending tests (ASTM D790) were performed to quantify the effects of nanoclay loading on flexural strength, modulus, strain, and fracture energy. The results showed that 3 wt.% of 3-GPTS-modified nanoclay produced the highest improvements, increasing flexural strength by 52%, flexural modulus by 96%, and fracture energy by 195% compared with the unfilled laminate. These enhancements were attributed to improved nanoparticle dispersion, increased matrix stiffness, and stronger interfacial bonding between the epoxy matrix, basalt fibers, and aluminum sheets. At 5 wt.% loading, agglomeration reduced strength and toughness despite further increases in modulus. FESEM analysis confirmed enhanced fiber–matrix adhesion and reduced fiber pullout in the modified nanoclay samples. The findings demonstrate that controlled incorporation of surface-modified nanoclay is an effective strategy for improving the bending performance of basalt-based FMLs, offering potential benefits for lightweight structural applications in aerospace and transportation.