Wear and friction behaviour of TiAl matrix self-lubricating composites filled with WS2, MoO3 or multilayer graphene

Abstract

To further understand the lubrication effects and mechanisms of lamellar solid lubricants, wear and friction behaviours of TiAl matrix self-lubricating composites (TMSC) filled with WS₂, MoO₃ or multilayer graphene (MLG) are comparatively investigated under different counterface materials. Tribological results indicate that wear and friction properties of TMSC are significantly improved by adding WS₂, MoO₃ or MLG. Specifically, TMSC filled with MoO₃ (TM) have lower friction coefficients and wear rates than TMSC filled with WS₂ (TW), while TMSC filled with MLG (TG) have the lowest friction coefficients and wear rates. Meanwhile, EPMA, AFM and FESEM analyses present significant differences in worn surfaces of TMSC. Definitely, the worn surfaces of TM exhibit lighter damage and comparatively more compact films than those of TW; in contrast, the worn surfaces of TG exhibit the lightest damage and the most compact films. It can be concluded that WS₂, MoO₃ and MLG actually possess different lubrication effects and mechanisms.