Effect of fabrication process on the microstructure and mechanical performance of carbon fiber reinforced PEEK composites via selective laser sintering

Carbon fiber reinforced PEEK (CF/PEEK) composites via selective laser sintering (SLS) are highly promising technologies for the fabrication of polymer-based components with excellent mechanical behavior. In order to further enhance the performance of SLS-CF/PEEK composites, the mixed CF/PEEK powders are designed and CF/PEEK composites are fabricated via SLS under different fabrication process parameters. The effect of laser power, layer thickness, paving speed, fiber weight fraction, and fiber length on the microstructure and mechanical performance along the powder spreading direction is investigated for SLS-CF/PEEK. The results show that the failure strength of 117 MPa is achieved while the layer thickness of 0.08 mm is adopted. Moreover, the fiber weight fraction of 15% is proven to be suited during the fabrication of SLS-CF/PEEK. The maximum failure strength is better than the results of SLS-CF/PEEK with the fiber weight fraction of 10%, and the average elastic modulus reaches 8400 MPa, which is the best result among those published works. In addition, it is found that the correlation between the failure strength and paving speed is non-monotonic, and the higher strength is obtained when the longer carbon fiber is used. Different from the distinct trends in failure strength, the sensitivity of modulus is much less obvious for SLS-CF/PEEK. This work provides guidance for the printing of high-strength CF/PEEK composites.