High-temperature sliding wear behavior of an intermetallic γ-based TiAl alloy

The high-temperature sliding wear behavior of the gamma-based TiAl alloy TNM-B1 was investigated using a pin-on-disk apparatus up to 800 degrees C in air under variation of the counterpart material. Sliding TNM-B1 against a Ni-based pin led to approximately twice as high wear losses compared to like-on-like wear tests up to 400 degrees C. These severe wear losses were verifiably attributed to a strong material transfer from the TiAl surface to the pin already existing at low temperatures. Moreover, it was proven that there is a distinctive temperature dependent transition from severe to mild wear for both sliding couples due to the formation of protective oxide scales above 600 degrees C. In this regard, Al- and Ti-rich oxide scales formed on the worn surfaces minimizing direct metal-to-metal contact.