Page 78 - MSAM-2-3

Materials Science in Additive Manufacturing Additive manufacturing of SiC composite

A B

Figure 26. Comparison of three-point bending strength and fracture toughness test results for carbon fiber/silicon carbide (C /SiC) (polyethylene
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terephthalate glycol) with 0.8 mm nozzle aperture and C /SiC compound with 1.0 mm nozzle aperture. (A) Three-point bending. (B) Fracture toughness.
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Figure 27. Schematic of phase evolution of carbon fiber/polylactic acid and carbon fiber/polyethylene terephthalate glycol during precursor infiltration
pyrolysis process.

strength and fracture toughness of the C /SiC (PETG) C /PLA and C /PETG is shown in Figure 27. This is the reason
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f
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composites, achieving an average bending strength of why the final bending strength and fracture toughness of the
93.79 MPa and a fracture toughness of 2.03 MPa·m . The 1.0-C /SiC (PETG) composites with an ILD of 1.3 mm were
1/2
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bending strength and fracture toughness were significantly improved compared to the 0.8-C /SiC (PETG) with an ILD
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improved by 112.5% and 120.7%, respectively, compared of 1.2 mm, even though the ILD was not reduced.
to the largest group of 0.8-C /SiC (PETG), and by 96.5%
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and 95.2%, respectively, compared to the largest group of 4. Conclusions
0.8-C /SiC (PLA). The improvement in bending strength In this paper, the continuous carbon fiber-reinforced SiC
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and fracture toughness due to the increase in nozzle was fabricated through green parts additive manufacturing
aperture is perhaps caused by the increase in nozzle and PIP post-ceramicization. The main conclusions are as
aperture and in the amount of prepreg delivered from the follows:
nozzle, resulting in an increase in the spreading width of (i) The bending strength of green part specimens
the deposition line, more uniform spreading of fibers in increases with the decrease of ILD. The maximum
the deposition line, a decrease in the fiber spacing between bending strength for C /PETG composite of 169.48
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deposition lines in the deposition layer, which corresponds MPa was achieved when the ILD was 1.0 mm, while
to an increase in the equivalent fiber density within a that for C /PLA composite was 155.83 MPa when the
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single layer, and a decrease in the fiber bundle-to-bundle ILD was 1.4 mm.
spacing in green parts. The spacing will be reduced, so that (ii) The apparent porosity and bulk density of the samples
the macroscopic pores of the green parts will be reduced, from the green parts to the first-cycle PIP change
thus allowing more uniform impregnation of the ceramic significantly, mainly because the high-temperature
precursor into the macroscopic pores between and within pyrolysis in the first PIP process carbonizes the resin
the fiber bundles, and eventually improving the mechanical in green part samples, thus producing a large number
properties of the C /SiC composites; the difference between of pores between the fiber bundles and between the
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Volume 2 Issue 3 (2023) 17 https://doi.org/10.36922/msam.1604