Mechanical investigation and microstructure performance of a two-matrix continuous carbon fibre composite fabricated by 3D printing

This research aims at systematically investigating the mechanical performance of three-dimensional printed continuous carbon fibre reinforced thermoset and thermoplastic composites (CFRTSTPCs) under different processing aspects, such as the nozzle temperature, fibre impregnation and inter-/intra-layer boundness. For this purpose, the fused filament fabrication (FFF) technique is applied. Two-matrix continuous carbon fibre composites have indeed the potential to combine the easiness of impregnation of thermoset matrix composites with the versatility of thermoplastic matrix composites, especially in nozzle based additive manufacturing, but they have not yet been studied in a systematic manner. Firstly, thermo-gravimetric analysis and micro-computed tomography scanning of an impregnated fibre bundle are performed to obtain the raw materials thermal stability. Maximum flexural strength of 294 MPa and modulus of 32.5 GPa are obtained for the continuous carbon fibre specimens. Microscopic images and micro-CT analysis are then utilized to manifest the interfacial bonding and void distribution in the two and three-dimensions, respectively. Dynamic mechanical analysis is used to obtain the thermo-mechanical behaviour of the printed specimens. Finally, the processing window is provided based on the analysis of variance for different process parameters. This research shows that the printing process of CFRTSTPCs with controlled capabilities has excellent potential to manufacture low-cost composite parts in the industrial field.