Mechanical and energy absorption behaviors of 3D printed continuous carbon/Kevlar hybrid thread reinforced PLA composites

Over the last few years, three-dimensional printing(3DP) technology has evolved to incorporate composite materials. However, using material extrusion (ME) technology, it is still difficult to improve the stiffness with stable elongation and energy absorption of continuous fiber reinforced composites at the same time. This study aimed to 3D print hybrid threads by merging several types of continuous Kevlar and Carbon fibers. Which were created using material extrusion 3D printing to accomplish cooperative ductility and brittleness augmentation. To analyze the mechanical performance and reveal the failure and deformation mechanisms, tension tests, three-point bending tests, and drop hammer impact tests were performed. The proposed hybrids have substantially greater flexural modulus, flexural strength, tension modulus, and tension strengths with absorbed energies than standard single type fiber composites. Crack resistance during impact test of hybrid composites was enhanced by over 91% compared to carbon fiber non-hybrid composites. SEM images of hybrid specimens provided an insight of the failure mechanisms, resulting in stable hybrid composites. Positive hybrid effect further demonstrates its great energy absorption capacity.