Effect of Ag and Ti3SiC2 on Tribological Properties of TiAl Matrix Self-lubricating Composites at Room and Increased Temperatures

Dry sliding tribological properties of TiAl matrix self-lubricating composites (TMSC) containing Ag, Ti3SiC2, Ag and Ti3SiC2 were investigated from 25 to 800 A degrees C under ball-on-disk test conditions against Si3N4 counterface under the same conditions of 10 N-0.234 m/s. The results indicated that the tribological properties were strongly dependent on the lubricant additives. TMSC with the addition of Ag and Ti3SiC2 (TAT) exhibited the lower friction coefficients (0.32-0.43) and less wear rates (1.23-4.13 x 10(-4) mm(3) N(-1)m(-1)) in the wide temperature range of 25-800 A degrees C. The excellent tribological properties of TAT over the wide temperature range were attributed to the synergetic effect of Ag and Ti3SiC2 lubricants, silver diffusion forming a rich-silver smooth tribo-film on the frictional surface of TAT at low and moderate temperatures from 25 to 400 A degrees C, while Ti3SiC2 oxidation reaction forming rich-oxide tribo-film on the worn surface of TAT at higher temperatures of 600 and 800 A degrees C.