Dry-Sliding Tribological Properties of TiAl Alloys and Ti{sub 2}AlN/TiAl Composites at High Temperature

The dry-sliding tribological properties of TiAl alloy and its composite Ti{sub 2}AlN/TiAl were investigated comparatively in the temperature range of 25-800 °C. The wear test results showed the wear resistance of TiAl alloy and Ti{sub 2}AlN/TiAl composite from 25 to 400 °C was poor, but it improved obviously when temperature was above 600 °C. Also, 15 vol.% incorporation of Ti{sub 2}AlN particles was beneficial to improve the friction and wear properties of TiAl. Protective oxide layer generated on the wear surface of 15 vol.% Ti{sub 2}AlN/TiAl composite from 25 to 400 °C, hence, the wear resistance improved. Ti{sub 2}AlN particles played a load-carrying role and inhabited the delamination of enamel layer effectively when the temperature was above 800 °C. Overall, Ti{sub 2}AlN particles which acted as hard spots changed the state of wear surface and further provided a second phase strengthening effect, which resulted in the difference in tribological behaviors between TiAl alloy and its composite.