Effect of applied load on tribological behaviour of Ti–48Al–2Cr–2Nb alloy under oil-lubricated condition

With their low weights and excellent mechanical properties, TiAl alloys are expected to be applied in pistons to achieve energy savings and emissions reductions in internal combustion engines. The tribological behaviours of the Ti-48Al-2Cr-2Nb alloy against the QT600-3 material at different applied loads under oil-lubricated condi-tions were investigated in this study. The results showed that as the load increased, the friction coefficient and wear-scar volume significantly decreased. The wear surface of the TiAl alloy was analysed using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The wear mechanism of the TiAl alloy under oil lubrication conditions was mainly the combined effect of adhesive wear and oxidation wear, different from the wear mechanism under dry-friction conditions. Furthermore, by observing the cross-sectional morphology of the TiAl alloy after focused ion beam, it was found that the QT600-3 wear debris had compacted and accumulated on the surface of the TiAl alloy, preventing further contact between the TiAl alloy and the QT600-3. This study has the potential to accelerate the application of the Ti-48Al-2Cr-2Nb alloy in lightweight pistons.