High-temperature tribological performance and wear mechanisms of GH90–K4169 superalloy friction pairs

The rapid development of high-end equipment manufacturing has resulted in increasingly severe operating conditions for modern mechanical systems, creating higher demands for tribological reliability and thermal stability in friction-pair materials. Although K4169 and GH90 high-temperature alloys possess excellent intrinsic yield strength and creep resistance, their tribological behaviour under elevated temperatures remains insufficiently understood. In this work, the friction and wear characteristics of K4169–GH90 pairs were systematically evaluated through tribological testing and micromorphological analyses. The results show that temperature exerts a significant influence on their tribological performance. With increasing temperature, the wear rate of the K4169 disk decreases from 2.32 × 10 −3 mm 3 /(N·m) to 0.65 × 10 −3 mm 3 /(N·m), whereas the wear rate of the GH90 pin increases from 4.77 × 10 −4 mm 3 /(N·m) to 2.95 × 10 −4 mm 3 /(N·m). The superior hardness and toughness of GH90 promote the formation of loose oxidised debris and metal-transfer films on the K4169 surface at elevated temperatures. These adherent products progressively accumulate during sliding, roughening the disk surface. Oxidation on K4169 remains largely confined to adhesion zones and is less severe than that on GH90, resulting in a thinner oxide layer. As temperature rises, accelerated oxidation thickens the oxide layer and aggravates adhesive wear, generating additional adhered material. Overall, the K4169–GH90 friction pair demonstrates favourable high-temperature frictional behaviour, providing essential data and mechanistic insights for use in extreme thermal environments.