Wear resistance of TiAl intermetallics by plasma alloying and plasma carburization

The duplex treatment of plasma carburization on plasma alloyed TiAl with Nb was carried out in order to improve the tribological properties of TiAl. Dry sliding wear behavior of the duplex-treated TiAl was investigated by using pin-on-disk wear testing method with the counterface of a high carbon steel compared with those of untreated and plasma-carburized TiAl. The microstructure of the existed phases in the surface layer and the distribution of the carbon element in the surface layer were characterized using optical microscopy, scanning electron microscopy, glow discharge spectrum and X-ray diffraction. The results showed that the duplex-treated TiAl is effective in enhancing the wear resistance of TiAl due to a low coefficient of friction and a low wear volume. The existence of NbC and Nb2C carbides and excessive carbon are the main contribution to the tribological performance of TiAl. At the same time, an increased thickness in the hardened layer by NbC and Nb2C carbides and carbon element is also effective in improving the tribological performance of TiAl.