Additive manufacturing of carbon fiber reinforced ceramic matrix composites based on fused filament fabrication

For the first time, carbon fiber reinforced ceramic matrix composites (CMC) were successfully fabricated by additive manufacturing (AM) using the fused filament fabrication (FFF) technology, filaments ("CF-PEEK") with thermoplastic polyetheretherketone (PEEK) as the matrix and C-precursor, and carbon short-fibers (< 250 mu m) as reinforcements. In order to prevent a re-melting of the as-printed CFRPs (C-fiber reinforced plastics) during pyrolysis at 1000 <degrees>C in N2ensuring the freedom of design and complex parts, a prior crosslinking step at 325 degrees C with a dwell time of 48 h in air was introduced to stabilize and crosslink the CFRP. Due to the stabilization and the printing of degassing channels for the pyrolysis, near net shape and complex CMC parts with different C-fiber orientations (0 degrees; +/- 45 degrees; 90 degrees) were obtained by the liquid siliconization infiltration process (LSI). The manufactured C/C-SiC parts were characterized regarding their microstructure and mechanical properties. The reinforcing C-fibers were successfully protected during the LSI-process and flexural strengths of almost 60 MPa were obtained.