Investigations on the mechanical properties of PLA/Flax fibre composites obtained by Fused Filament Fabrication

The additive manufacturing technique has been used more and more recently because of the advantages it offers, in particular in terms of the geometrical complexity of the produced parts. Recently, researchers are increasingly interested in flax fibres as a natural reinforcing for polymer-based filaments manufactured via the Fused Filament Fabrication (FFF) method, allowing their mechanical properties to be improved compared to the pure polymer. The mechanical properties of flax fibre-reinforced polylactic acid composite, obtained by the FFF process, are nevertheless not well known. The purpose of this study is to characterise the effect of manufacturing conditions as feed rate, build orientations, and layer thickness on the mechanical performance of PLA/Flax fibre composite. The mechanical characteristics of the materials were explored at the part scale considered as macroscopic scale and at the filament scale considered as mesoscopic scale. Microstructural analyses are performed to reveal the rupture mechanism at the microscopic scale.