James W. Kemp (1), Abel A. Diaz (2), Elizabeth C. Malek (3,4), Brendan P. Croom (3), Zlatomir D. Apostolov (3), Surya R. Kalidindi (2), Brett G. Compton (1), Lisa M. Rueschhoff (3)
Additive Manufacturing, 44, August 2021. DOI: 10.1016/j.addma.2021.102049

Keywords

Ultra-high temperature ceramics; Direct ink writing; Preceramic polymer; Zirconium diboride; Silicon carbide; Ceramic matrix composite

Abstract

Ultra-high temperature ceramics (UHTCs) are of interest for thermally- and/or mechanically- extreme environments because of their high melting temperatures (> 3000 °C) and ablation resistance. More widespread use is limited by low fracture toughness and inability to be processed into complex-shaped components. Here, we report the production of fiber-reinforced UHTC matrix composites (UHTCMCs) formed via the additive manufacturing technique of direct ink writing (DIW). Slurry 'inks' were developed containing up to 47.5 vol% of the UHTC zirconium diboride (ZrB2), up to 10 vol% chopped silicon carbide fiber (SiCf), and a silicon carbide (SiC) precursor polymer. Lattice structures and flexural specimens were printed and pyrolyzed to form UHTCMCs with aligned (relative to the print direction) SiCf in the ZrB2 – SiC matrix. Flexural strength of fiber-containing parts is presented, and fiber alignment due to deposition is analyzed with X-ray computed tomography. Defects that occurred during the DIW process, and their probable causes and mitigation strategies are also discussed.

How Our Software Was Used

Dragonfly was used for image analysis.

Author Affiliation

(1) University of Tennessee, Knoxville, TN, USA.
(2) Georgia Institute of Technology, USA.
(3) Air Force Research Laboratory, USA.
(4) Southwestern Ohio Council for Higher Education, USA.