Influence of Fiber Layer Stacking, Annealing at Different Pressures and Fiber Volume Fraction on Flexural Mechanical Properties of 3D Printed Reinforced Composites

This article investigates the impact of fiber layer stacking and annealing at different pressures on flexural mechanical strength and performance of carbon fiber-reinforced 3D-printed composites. Furthermore, the effect of fiber volume fraction on flexural properties of fiber layer stacking was also investigated. Results demonstrated that bordered fiber layer stacking offered the greatest flexural strength and modulus of 221.47 MPa and 11.77 GPa compared to distributed and centered fiber layer stacking. Owing to more fiber layers at borders that provide extra support by an efficient load transfer and are in direct contact with the loading nose of testing equipment. Annealing at pressure of 350 kPa for bordered fiber layer stacking achieved maximum flexural strength and modulus of 316.89 MPa and 12.61 GPa, compared to distributed and centered fiber layer stacking. Microstructural observations revealed that annealing at 350 kPa pressure resulted in consolidation of matrix-fiber interface, as cavities/pores introduced during extrusion were eradicated. At a fiber volume fraction of 27.75%, maximum flexural strength and modulus of 238.88 MPa and 13.69 GPa are achieved by bordered fiber layer stacking compared to other stackings. As fiber volume increases at the outer layers, additional reinforcement is offered to bear load, and the effectiveness of load transfer improves, thereby intensifying flexural mechanical strength and performance.