Friction and Wear Behavior of Laser-Cladded TiAl Coating on TC4 Substrate from Room Temperature to 800 degrees C

TiAl intermetallic coatings were prepared on TC4 plates by laser cladding. The phase composition and microstructure of the coatings were investigated. The high-temperature oxidation mechanism and the friction and wear behaviors of the coating over a wide temperature range were analyzed and discussed. The results show that the obtained coating was mainly composed of a two-state structure of alpha(2)-Ti3Al and gamma-TiAl. The TiAl coating exhibited excellent wear resistance at both room temperature and high temperatures, and its wear rate at room temperature was 30.8% lower than that of TC4 because of the uniform and compact structure. At 600 degrees C and 800 degrees C, a self-lubricating Al2O3-TiO2 mixed oxide film was formed, reducing the friction coefficient to 0.295 and 0.229, respectively. At 600 degrees C and 800 degrees C, the wear rate was 8.5 and 3.5 times lower than that at 400 degrees C, where the oxide film was not integrally formed.