Fabrication and Characterization of Plasma-Sprayed Carbon-Fiber-Reinforced Aluminum Composites

Carbon fiber (C-f)/Al specimens were fabricated by plasma-spraying aluminum powder on unidirectional carbon fiber bundles (CFBs) layer by layer, followed by a densification heat treatment process. The microstructure and chemical composition of the C-f/Al composites were examined by scanning electron microscopy and energy-dispersive spectrometry. The CFBs were completely enveloped by aluminum matrix, and the peripheral regions of the CFBs were wetted by aluminum. In the wetted region, no significant Al4C3 reaction layer was found at the interface between the carbon fibers and aluminum matrix. The mechanical properties of the C-f/Al specimens were evaluated. When the carbon fiber volume fraction (CFVF) was 9.2%, the ultimate tensile strength (UTS) of the C-f/Al composites reached 138.3 MPa with elongation of 4.7%, 2.2 times the UTS of the Al matrix (i.e., 63 MPa). This strength ratio (between the UTS of C-f/Al and the Al matrix) is higher than for most C-f/Al composites fabricated by the commonly used method of liquid-based processing at the same CFVF level.