Tribological behaviors and mechanisms of Ti3AlC2

Abstract

Tribological behaviors and the relevant mechanism of a highly pure polycrystalline bulk Ti 3 AlC 2 sliding dryly against a low carbon steel disk were investigated. The tribological tests were carried out using a block-on-disk type high-speed friction tester, at the sliding speeds of 20-60 m/s under a normal pressure of 0.8 MPa. The results showed that the friction coefficient is as low as 0.1$0.14 and the wear rate of Ti 3 AlC 2 is only (2.3-2.5) Â 10 )6 mm 3 /Nm in the sliding speed range of 20-60 m/s. Such unusual friction and wear properties were confirmed to be dependant dominantly upon the presence of a frictional oxide film consisting of amorphous Ti, Al, and Fe oxides on the friction surfaces. The oxide film is in a fused state during the sliding friction at a fused temperature of 238-324°C, so it takes a significant self-lubricating effect.

Strengthening and tribological surface self-adaptability of Ti3AlC2 by incorporation of Sn to form Ti3Al(Sn)C2 solid solutions

“…Thus, instead of being present in a fused state, the oxide film must exist in a soft state on the friction surface during sliding friction. This behaviour is also quite different from that exhibited by the oxide film on the Ti 3 AlC 2 friction surface, where the oxide film consisted of an amorphous mixture of Ti, Al and Fe oxides; the melting point of the oxide is between 238 and 314 1C, which indicates that the material must be in a fused state on the friction surface during sliding friction [14].…”

“…Compared with the tribological behaviour of Ti 3 AlC 2 [13,14], partially substituting Sn into Al sites to form solid solutions did significantly change the tribological properties of the solid solution. Sn affected the combination of the mixed oxides with the tin oxide.…”

“…It has been observed that Ti 3 AlC 2 exhibits an unusual combination of properties [9][10][11][12], such as excellent resistance to oxidation and to thermal shock, unusual brittle-to-ductile character, damage tolerance, being readily machinable, and having good electrical and thermal conductivity. Ti 3 AlC 2 also demonstrates good tribological properties [13][14][15][16], particularly at high sliding speeds [13,14]. Such unique properties make Ti 3 AlC 2 suitable for use in structural components for hightemperature and tribological applications.…”

“…In a previous study [13][14][29][30], researchers found that self-generating tribofilms covered the surfaces of Ti 3 AlC 2 or Ti 3 SiC 2 and were responsible for tribological behaviours. Both types of tribofilms, which were composed of Ti, O, Al and Fe for Ti 3 AlC 2 bulk [13,14] and of Ti, O, Si and Fe for Ti 3 SiC 2 bulk [29,30], were likely composed of the oxide of A site elements in the MAX phase. The authors thus postulated that a frictional film can be adapted to a wide range of tribological conditions if elements are partially substituted into the A sites of solid solutions.…”

Fabrication, Mechanical Properties, and Tribological Behaviors of Ti3Al0.8Sn0.4C2 Solid Solution by Two‐Time Hot‐Pressing Method

“…It is interesting that in our previous work, we found both the surfaces of Ti 3 SiC 2 and Ti 3 AlC 2 were covered by the friction films when dry sliding against low‐carbon steel. It was argued that self‐generating tribofilms, composed of Ti, O, Si, and Fe for Ti 3 SiC 2 bulk, as well as Ti, O, Al, and Fe for Ti 3 AlC 2 bulk, were responsible for this behavior. No matter Ti 3 SiC 2 or Ti 3 AlC 2 bulk, the tribofilms were attributed to the oxide of A‐site elements of MAX phase.…”