Fabrication and microstructure evolution of Csf/ZrB2-SiC composites via direct ink writing and reactive melt infiltration

Fiber damage and uniform interphase preparation are the main challenges in conventional short fiber reinforced ceramic matrix composites. In this work, we develop a novel processing route in fabrication of short carbon fiber reinforced ZrB2-SiC composites (C-sf/ZrB2-SiC) overcoming the above two issues. At first, C-sf preforms with oriented designation and uniform PyC/SiC interphase are fabricated via direct ink writing (DIW) of short carbon fiber paste followed by chemical vapor infiltration. After that, ZrB2 and SiC are introduced into the preforms by slurry impregnation and reactive melt infiltration, respectively. Microstructure evolution and optimization of the composites during fabrication are investigated in detail. The as-fabricated C-sf/ZrB2-SiC composites have a bulk density of 2.47 g/cm(3), with uniform weak interphase and without serious fiber damage. Consequently, non-brittle fracture occurs in the C-sf/ZrB2-SiC composites with widespread toughening mechanisms such as crack deflection and bridging, interphase debonding, and fiber pull-out. This work provides a new opportunity to the material design and selection of short fiber reinforced composites.