Keywords and Phrases
Additive Manufacturing; Boron Carbide; Freeze-form Extrusion Fabrication
"Boron carbide is a safe, alternative to beryllium as a material for aerospace structures since it is also light-weight and exhibits high strength. This paper discusses a study of the Freeze-form Extrusion Fabrication (FEF) process to fabricate parts from boron carbide. Process parameters and hardware were modified to fabricate boron carbide specimens free of printed defects. Four-point bending tests were performed to measure the flexural strength of fabricated specimens. Observations of the presence of voids caused by ice crystals in fabricated parts led to further development and characterization of the boron carbide paste used with the FEF process. Additives were selected and tested to observe their effect on the size of the ice-crystal voids. Scanning electron microscopy was used to observe the voids left from the ice crystals after part sintering. Post-image analysis was performed to measure approximate sizes of ice-crystal voids and these results were summed up in a void size distribution. Glycerol in a concentration of 25 wt% by water increased the flexural strength of test bars from 58.1 MPa to 67.4 MPa and the sintered relative density from 76.2% to 85.0%. The standard deviation of the flexural strength decreased from 23.0 to 14.5 MPa. None of the additives considered reduced the sizes of the ice crystal voids desirably as the highest relative density of the sintered test bars achieved was only 85.0%."--Abstract, page iii.
Leu, M. C. (Ming-Chuan)
Landers, Robert G.
Mechanical and Aerospace Engineering
M.S. in Mechanical Engineering
Missouri University of Science and Technology
ix, 81 pages
© 2015 Aaron Scott Thornton, All rights reserved.
Thesis - Open Access
Ceramic materials -- Extrusion
Solid freeform fabrication
Electronic OCLC #
Thornton, Aaron Scott, "Freeze-form extrusion fabrication of boron carbide" (2015). Masters Theses. 7439.