High Temperature Wear Behaviors of TiAl–TiB2 Composites

Abstract

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.