Enhanced Interfacial Microstructure Evolution and Mechanical Properties of CF/Al–Mg Composites with Optimal Interconnected Coating

In the present study, the Ni coatings on the surface of carbon fibers (CFs) were purposely regulated to provide the enhanced interfacial microstructure evolution and mechanical properties of CF reinforced Al–Mg matrix (CF/Al–Mg) composites. With increasing the pH value and deposition time, the coating thickness increased with the formation of island-like agglomeration as the pH value was 4.5. Based on the stable electroless plating process, different thicknesses of interconnected coatings were applied in the CF/Al–Mg composites fabricated by a semi-solid rolling process in open space. With the optimal thickness of 2.15 μm, the relative density of the composites increased from 89.7 % to 98.1 %, compared with that of the composites with the thickness of 0.54 μm due to eliminated un-infiltration defects. Simultaneously, optimized fiber dispersion and interfacial behavior were obtained, leading to effective load transfer, more energy absorption and consequently significant enhanced mechanical properties. The ultimate tensile strength (UTS) of the composites was 183 MPa with the largest improvement, which was 96.8 % higher than that of the matrix.