Mechanical properties of aluminum bonded joints reinforced with functionalized boron nitride and boron carbide nanoparticles

In the presented study, the effect of hexagonal boron nitride and hexagonal boron carbide nanoparticles on the strength of adhesively bonded joints was investigated experimentally. Hexagonal boron nitride nanoparticles were functionalized using 3-(aminopropyl) triethoxysilane to improve adhesion and increase the interaction between epoxy and nanoparticles. Similarly, h-B4C nanoparticles were functionalized by using 3-(glycidyloxypropyl) trimethoxysilane. New structural nano adhesives were produced by reinforcing the functionalized nanoparticles into epoxy at different proportions (0.5 wt.%, 1.0 wt.%, 2 wt.%, 3.0 wt.%, 4.0 wt.%, and 5.0 wt.%). Two different epoxies with different viscosity values (MGS-LR285 and Araldite 2011) were used as adhesives, and aluminum alloy (AA2024-T3) was chosen as an adherend. Tensile test was carried out to determine the failure load of the adhesive joints, and the fracture surface morphology was examined after the test Additionally, Scanning electron microscopy and energy dispersion X-ray spectroscopy (SEM-EDS) analysis was performed to observe the distribution of boron nanoparticles in the adhesives. The experimental results showed that the reinforcement of hexagonal boron nitride and boron carbide nanoparticles to the adhesives increased the joint strength substantially depending on the reinforcement ratio and viscosity of the adhesives. The maximum increase in failure loads was achieved by adding 1 wt.% functionalized boron nitride to high viscosity Araldite 2011 adhesive and 2 wt.% to low viscosity MGS-LR285 adhesive, and the ratio of increase in failure loads is 31% and 63%, respectively. Moreover, by adding 2 wt.% functionalized boron carbide nanoparticles to the Araldite 2011 and MGS-LR285 adhesives, the strength of the joints increased by about 27% and 70%, respectively.