Effects of Chopped Carbon Fiber on the Forming, Structure, and Mechanical Properties of CCF/SiC Composites Fabricated by Selective Laser Sintering and Reactive Melt Infiltration

Abstract

Silicon carbide (SiC) composites are fabricated by selective laser sintering (SLS) combined with reactive melt infiltration (RMI) using SiC powder mixed with various contents (0–32 vol%) of chopped carbon fiber (CCF) as reinforcement phase and carbon source. The introduction of an appropriate amount of CCF can reduce the shrinkage and step effect caused by slicing, improving the forming quality of the CCF/SiC preforms after pyrolysis. Meanwhile, as a carbon resource, CCF can react with molten silicon to form the β‐SiC, improving the mechanical properties of CCF/SiC composites. The result shows that the CCF/SiC powder shows excellent fluidity, and the angle of repose of the CCF/SiC powder is 32–40° when the proportion of CCF is less than 24 vol%. CCF/SiC preforms shrinkage is lower than 1.74% and 1.94% along the nonadditive and additive manufacturing directions, respectively. Compared without CCF, the bending strength and fracture toughness of the CCF/SiC composites with 8 vol% CCF improve from 137.9 MPa and 2.69 MPa m1/2 to 177.1 MPa and 3.10 MPa m1/2, respectively. This study is believed to provide a new strategy for additive manufacturing of high‐performance CCF/SiC composites with high CCF content by SLS.