Fig 1. Flowchart of nano-SiCp/A356 nanocomposites fabricating process.

Fig. 2. Morphologies of the as-received powders: (a) nano-SiC powders and (b) pure Al powders.

Fig. 3. Morphologies of the composite granules with 8 wt% nano-SiC particles milled under different ball-to-powder weight ratio and rotation speed: (a) 9:1, 240 rpm; (b) 9:1, 300 rpm; (c) 5:1, 300 rpm; and (d) surface of the composite granule in (c).

Fig. 4. SEM microstructures of the composite granules with different nano-SiC particle fractions: (a) 2 wt%, (b) 4 wt% and (c) 8 wt%.

Fig. 5. Composition analysis results of the composite granules: (a) XRD of the granules, (b) EDS of the bright white spots and (c) plate like phase in Fig. 4(a).

Fig. 6. Morphologies and surface characterizations of the composite granules with 8 wt% nano-SiC particles milled for different times: (a) and (b) for 2 h, (c) and (d) for 4 h, (e) and (f) for 7 h; (b), (d) and (f) are the high magnification of (a), (c) and (e), respectively (ball-to-powder weight ratio and rotation speed were 5:1 and 300 rpm, respectively).

Fig. 7. Microstructure of squeeze cast A356 alloy matrix with UV treatment and solidified under 200 MPa.

Fig. 8. Metallographic structures of 1 wt% nano-SiCp/A356 composites with UV and solidified under (a) 200 MPa and (b) 0 MPa squeeze pressure.

Fig. 9. SEM microstructures of squeeze cast 1 wt% nano-SiCp/A356 composites with UV: (a) and (b) in eutectic region, (c) and (d) in primary α-Al phase near eutectic region; (b) and (d) are the high magnification of (a) and (c), respectively.

Fig. 10. Distribution of the nano-SiC particles in squeeze cast 1 wt% nano-SiCp/A356 composites without UV: (a) low magnification and (b) high magnification.

Fig. 11. Shrinkage pores between the eutectic Si and nano-SiC particle clusters in squeeze cast 1 wt% nano-SiCp/A356 composites without UV.