Microstructure characterization of SiC nanowires as reinforcements in composites

• Cross-section microstructure of SiC nanowires was observed in Al composite.
• Cylindrical with smooth surface or bamboo shape SiC nanowires were found.
• The cylindrical and bamboo shaped SiC nanowires were equivalent in structure.
• Structure of SiC nanowires was remodeled.
• SiC nanowires are composed of hybrid 3C-SiC and 2H-SiC structures.

SiC nanowires have been rarely investigated or explored along their axial direction by transmission electron microscopy (TEM). Here we report the investigation of the cross-section microstructure of SiC nanowires by embedding them into Al matrix. Morphology of SiC nanowires was cylindrical with smooth surface or bamboo shape. Cubic (3C-SiC) and hexagonal structure (2H-SiC) phases were detected by X-ray diffraction (XRD) analysis. High density stacking faults were observed in both the cylindrical and bamboo shaped nanowires which were perpendicular to their axial direction. Selected area electron diffraction (SAED) patterns of the cylindrical and bamboo shaped SiC nanowires both in the perpendicular and parallel direction to the axial direction were equivalent in the structure. After calculation and remodeling, it has been found that the SAED patterns were composed of two sets of diffraction patterns, corresponding to 2H-SiC and 3C-SiC, respectively. Therefore, it could be concluded that the SiC nanowires are composed of a large number of small fragments that are formed by hybrid 3C-SiC and 2H-SiC structures.

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