Mechanical properties and morphological characteristics of ARALL reinforced with TRGO doped epoxy resin

Abstract

Mechanical properties in tension, bending, fatigue and lap-shear in two different proportions (0.5%wt and 1%wt) of TRGO (Thermally Reduced Graphite Oxide) doped ARALL (Aramid Aluminium Laminate) were examined. The materials and their failure modes were characterized morphologically by examination through SEM (Scanning Electron Microscopy). Some mechanical properties of ARALL were improved when doped with 0.5% of TRGO, showing a significant increase of fatigue properties, as well as a change in fracture surface morphology. Tension andbending properties showed variable results and further studies should be carried out to arrive to definitive conclusions, while lap-shear testing showed lower shear values. The results were statistically validated through mono-factorial variance analysis. Comparing the present results with previous work on CNT (Carbon Nanotubes) doped ARALL, it can be stated that: (a) TRGO doped ARALL showed improved fatigue properties when compared with non-doped ARALL, but in a less effective way than doping with CNT, (b) TRGO doped ARALL tension properties showed no significant variation as compared with ARALL alone, showing no deleterious influence as in the CNT doping case, (c) TRGO doped ARALL bending properties resulted better than non-doped ARALL, but similar than those obtained when doping with CNT and (d) TRGO decreased the adherence between aramid fiber impregnated L20 epoxy resin and aluminium. These last results are sustained based on observed improvements as a percentage value, without a statistical variance analysis made on CNT doped ARALL.

New Advances and Future Possibilities in Forming Technology of Hybrid Metal–Polymer Composites Used in Aerospace Applications

“…There are four grades of ARALL composites, differing mainly in the grade of the base material (ARALL: 1-7075-T6; 2-2024-T3; 3-7075-T76; 4-2024-T8). ARALLs have not been widely used due to their low strength and durability on the metal-composite interface, low strength of the fibre-matrix connection, and high production costs [13][14][15]. CARALL is a laminate made of layers of a polymer composite reinforced with carbon fibres preimpregnated with epoxy resin and layers of aluminium [16][17][18].…”

“…Figure13. Distribution of residual stresses in shot peened NFML (reproduced with permission from[138]; copyright© 2021 Elsevier Ltd. All rights reserved).…”