Ordered metal substitution in Ti3AlC2 and the effect on tribological behaviors in a wide temperature range.

In this work, tribological properties of Ti 3 AlC 2 , Cr 2 TiAlC 2 , and Mo 2 TiAlC 2 MAX are evaluated in a wide temperature range of 25–800 ℃. By replacing the 4 f Wyckoff site Ti atoms of Ti 3 AlC 2 with Cr or Mo, the MAXs deliver lower coefficient of friction (COF) than Ti 3 AlC 2. Interestingly, as confirmed by the morphological, structural, and chemical analyses, the two MAXs are applicable in different temperatures. For Cr 2 TiAlC 2 , the lowest wear rate is 2.30 × 10−7 mm3 N−1 m−1 at 800 ℃, while the lowest wear rate of Mo 2 TiAlC 2 is achieved at room temperature of 3.83 × 10−7 mm3 N−1 m−1. These distinct tribological behaviors are ascribed to the altered M-A and M-C bindings, as well as the properties of the produced oxides. [ABSTRACT FROM AUTHOR]