Friction and wear behaviors of TC4 alloy with surface microporous channels filled by Sn-Ag-Cu and Al₂O₃ nanoparticles

To overcome the poor tribological performance of titanium alloys and broaden their applications in the rapidly developing aerospace industry, this paper studies the friction and wear behaviors of TC4 alloy with surface microporous channels filled by Sn-Ag-Cu (SAC) and Al₂O₃ nanoparticles using the dry sliding tests. Moreover, the synergistic lubricating mechanism of SAC4 and Al₂O₃ nanoparticles is also investigated in detail. The results show that TC4 alloy with surface microporous channels filled by SAC4 (50Sn-45Ag-5Cu) and 6 wt% Al₂O₃ nanoparticles (TC4-SACA3) presents excellent antifriction property and wear resistance over a wide range of temperatures and applied loads. Especially at 400 °C-10 N, TC4-SACA3 can obtain the smallest friction coefficients of 0.185 and the minimal wear rate of 3.6 × 10⁻⁵ mm³N⁻¹ m⁻¹, which is attributed to the synergistic effect of SAC4 and Al₂O₃ nanoparticles. During the sliding process, SAC4 can precipitate from the microporous channels under the heat-force driving and then gradually form a smooth lubricating film on the friction surface. Meanwhile, some Al₂O₃ nanoparticles wrapped by lubricant SAC4 can improve the load carrying capacity of lubricating film, and the other exposed Al₂O₃ nanoparticles on the friction surface play a role of “micro-bearings” between the friction pairs.