Large-scale material extrusion-based additive manufacturing of short carbon fibre-reinforced silicon carbide ceramic matrix composite preforms

Figures & data

Table 1. Compositions used for the C_sf/SiC slurries.

Sample	Solid loading (vol.%)	Solid loading of the ink		Liquid loading of the ink
		SiC (vol.%)	Csf (vol.%)	Distilled water (vol.%)
40-Csf/SiC	40	24	16	60
45-Csf/SiC	45	27	18	55
50-Csf/SiC	50	30	20	50

Dispersant: PEG accounts for 0.56 wt.% of the total solid mass.

Binder: MC accounts for 4 wt.% of the distilled water’s weight.

Figure 1. Fabrication of C_sf/SiC CMC preform by material extrusion based additive manufacturing.

Figure 2. (a) Log viscosity versus log shear rate plots; (b) log shear stress versus log shear rate of varying C_sf/SiC slurries with different solid loading.

Figure 3. (a) Cross-section images of filament under varying solid loading and nozzle diameter; (b) outlines and areas of filament cross-sections under varying solid loading and nozzle diameters (simulated by ImageJ).

Figure 4. The schematic of the measured line width of filaments.

Table 2. The measured line width (mm) of filaments under varying solid loading and nozzle diameter.

Nozzle diameter	0.6 mm			1.0 mm			1.5 mm
Solid loading	L1 (mm)	L2 (mm)	L1/L2	L1 (mm)	L2 (mm)	L1/L2	L1 (mm)	L2 (mm)	L1/L2
40 vol.%	1.71 ± 0.03	0.98 ± 0.02	1.73 ± 0.02	2.11 ± 0.03	1.19 ± 0.01	1.78 ± 0.02	2.91 ± 0.02	1.58 ± 0.01	1.84 ± 0.01
45 vol.%	1.32 ± 0.01	0.81 ± 0.03	1.63 ± 0.01	2.04 ± 0.02	1.20 ± 0.01	1.71 ± 0.02	2.90 ± 0.01	1.61 ± 0.01	1.80 ± 0.01
50 vol.%	0.90 ± 0.02	0.82 ± 0.01	1.10 ± 0.02	1.56 ± 0.01	1.25 ± 0.01	1.25 ± 0.01	2.08 ± 0.02	1.58 ± 0.01	1.32 ± 0.01

Figure 5. Images of specimens with single filament plus multi-layer structure under varying solid loading: (a) 40 vol.%; (b) 45 vol.% and (c) 50 vol.%. (nozzle diameter: 1.0 mm; layer height: 0.75 mm).

Figure 6. The height deviation of specimens with single filament plus multi-layer structure under varying solid loading.

Figure 7. Images of 50-C_sf/SiC specimens with two filaments plus multi-layer structure under varying nozzle diameter: (a) 0.6 mm; (b) 1.0 mm; and (c) 1.5 mm. (solid loading: 50 vol.%; layer height:75% of nozzle diameter).

Figure 8. The height deviation of specimens with two filaments plus multi-layer structure under varying nozzle diameter.

Figure 9. Images of 50-C_sf/SiC specimens with two filaments plus multi-layer structure under varying layer height: (a) 45%; (b) 60%; (c) 75%; and (c) 90% of the nozzle diameter (1.0 mm).

Figure 10. The height deviation of specimens with two filaments plus multi-layer structure under varying layer height.

Figure 11. (a) Schematic illustrations of extrusion process under various layer height and (b) schematic illustrations of the deposition of filament.

Figure 12. (a) The idealised wall; the printed walls with different angles from the vertical: (b) 10^o; (c) 20^o; (d) 30^o; (e) 40^o; (f) 45^o. The top layer interface was marked in black. (solid loading: 50 vol.%; nozzle diameter: 1.0 mm; layer height: 0.75 mm).

Table 3. The α of idealised structure and the α of printed structure.

α of idealised structure (^o)	α of printed structure (^o)
10	9
20	18
30	27
40	38
45	-

Figure 13. Images of large-scale C_sf/SiC CMC preform with out of plane structure.