Manufacturing of Conductive, Wear-Resistant Nanoreinforced Cu-Ti Alloys Using Partially Oxidized Electrolytic Copper Powder

Reactive powder composites Cu-(0–15%)TiH(2) containing up to 5% native Cu(2)O were manufactured by high energy ball milling and then hot-pressed to produce bulk nanostructured copper–matrix alloys reinforced by Cu(3)Ti(3)O inclusions. Two high-energy ball-milling (HEBM) protocols were employed for the fabrication of Cu-Ti alloys: single-stage and two-stage ball milling, resulting in an order of magnitude refinement of TiH(2) particles in the reactive mixtures. Single-stage HEBM processing led to the partial retention of Ti in the microstructure of hot-pressed specimens as the α-Ti phase and formation of fine-grained (100–200 nm) copper matrix interspersed with 5–20 nm Cu(3)Ti(3)O precipitates, whereas the two-stage HEBM led to the complete conversion of TiH(2) into the Cu(3)Ti(3)O phase during the hot pressing but produced a coarser copper matrix (1–2 μm) with 0.1–0.2 μm wide polycrystalline Cu(3)Ti(3)O layers on the boundaries of Cu grains. The alloy produced using single-stage HEBM was characterized by the highest strength (up to 950 MPa) and electrical conductivity (2.6 × 10(7) Sm/m) as well as the lowest specific wear rate (1.1 × 10(−5) mm(3)/N/m). The tribological performance of the alloy was enhanced by the formation of Cu(3)Ti(3)O microfibers in the wear debris, which reduced the friction coefficient against the Al(2)O(3) counter-body. The potential applications of the developed alloys are briefly discussed.