High Temperature Wear Behaviors of TiAl–TiB₂ Composites

In this article, the dry-sliding tribological behaviors of TiAl-based composites reinforced with 20 and 40 vol% in situ synthesized TiB₂ produced by a hot-press sintering process were investigated from room temperature (RT) to 800 °C. The results show that the high-temperature wear resistance of the TiAl alloy is improved by adding the TiB₂ particles under all the testing temperatures, and the more the TiB₂ reinforcement, the better the wear resistance is. This improvement is more significant at 600 °C and above, especially for the composite with 40 vol% TiB₂, whose wear rate is 4–10 times lower than TiAl at 600 and 800 °C. Accordingly, the wear mechanisms transfer from abrasion wear at low and moderate temperature (RT, 200 and 400 °C) to oxidation wear at high temperature (600 and 800 °C). In addition to the brittle-to-ductile transition of the materials and oxide layer formation, the phase transition of Al₂O₃ and TiO₂ may be partly responsible for the promising wear resistance at high temperatures.