Analysis of tribological behaviors and regulating functions at elevated temperatures of microchannel interfaces prepared in Ti-base alloys.

For improving the tribological behaviors of traditional Ti alloys, high-nickel Ti alloy with sinusoidal micropores was prepared by laser additive manufacturing (LAM). MgAl (MA), MA-graphite (MA-GRa), MA-graphenes (MA-GNs), and MA-carbon nanotubes (MA-CNTs) were respectively filled into the Ti-alloy micropores to prepare interface microchannels through high-temperature infiltration. In a ball-on-disk tribopair system, the tribological and regulating behaviors of the microchannels in Ti-base composites were elucidated. The results showed that the regulation functions of MA were noticeably improved at 420 °C, resulting in their superior tribological behaviors than those at other temperatures. It could be concluded that GRa, GNs, and CNTs combined with MA further enhanced the regulation behaviors compared to individual MA lubrication. The following regulation factors were responsible for the excellent tribological properties: the interlayer separation of graphite, which accelerated the plastic flow of MA, improved the interface crack self-healing of Ti-MA-GRa, and regulated the friction and wear resistance abilities. Compared with GRa, GNs were easier to slide, and helped to produce a greater deformation of MA, facilitating a good self-healing of cracks, and further enhancing the wear regulation of Ti-MA-GNs. CNTs showed good synergism with MA to allow the rolling friction, which effectively repaired the cracks to improve interface self-healing, resulting in a better tribological performance of Ti-MA-CNTs compared to Ti-MA-GRa and Ti-MA-GNs.