High temperature tribological behaviour of Al/Al₂O₃ composite coating on γ-TiAl

Abstract

To improve the high temperature wear resistance of Ti–46·5Al–1Cr–1·5V, an Al/Al₂O₃ composite ceramic coating was prepared on it by radio frequency sputtering. In this paper, microstructure, elements distribution, phase identification of the Al/Al₂O₃ composite coating were investigated. Also, its nanohardness and elastic modulus were examined. High temperature dry sliding wear behaviour at 300°C was analysed in details. The results indicated that the homogeneous and dense composite coating was about 20 μm thick. Additionally, the composite coating possessed higher H/E and H³/E² ratios than those of substrate. Compared to the substrate, the Al/Al₂O₃ composite coating recorded a lower friction coefficient and the volume loss of Al/Al₂O₃ coating was only 1/3 of the bare substrate under dry sliding conditions at 300°C. All the results demonstrated that the Al/Al₂O₃ coating has effectively improved the wear resistance of Ti–46·5Al–1Cr–1·5V at 300°C.

Keywords:

• γ-TiAl
• Al/Al₂O₃ composite coating
• High temperature wear resistance
• Tribological behaviour

Acknowledgement

This project was supported by the Fundamental Research Funds for the Central Universities, National Natural Science Foundation of China (grant no. 51174119), Aeronautical Science Foundation of China (grant no. 2012ZF52071).