FAST-Sintered Cu/Cf Composites: Wear and Corrosion Characteristics

Abstract This study examines the effects of fiber content, distribution, and interfacial bonding on the thermal, mechanical, and tribological properties of copper matrix composites reinforced with short carbon fibers (C f ), produced via rapid sintering. Uniform composite feedstocks were prepared by mixing gas-atomized pure copper powder with 40 and 60 vol.% copper-coated short carbon fibers using a 3D mixer. The resulting blends were consolidated through the field-assisted sintering technique at temperatures between 900 and 940 °C. Microscopic analysis confirmed a random distribution of the fibers within the matrix and compatible interfacial bonding with the copper. Thermal tests with a dilatometer showed that increasing C f content significantly reduced thermal conductivity and the coefficient of thermal expansion. Tribological tests under low (6 N) and high (20 N) loads demonstrated significantly lower friction coefficients, the lowest 0.2, for the composites compared to pure copper. However, wear rates increased at 20 N under ball-on-disk conditions. This was in contrast to pure copper. The reduced tensile strength of the composites relative to pure copper was attributed to the diminished load-bearing capacity of the short fibers. Pure copper showed shallow localized corrosion pits. In contrast, composites—especially with 60 vol.% C f exhibited— corrosion initiating at the fiber–matrix interface. The lowest corrosion rate was observed at 25 °C.