BEHAVIOR OF EUTECTIC Ti–Si–Zr TITANIUM ALLOYS  IN DIFFERENT FRICTION CONDITIONS 

Abstract

The tribological properties of heterogeneous Ti−Si−Zr titanium alloys with an e(β^*-Ti +  (Ti, Zr)₂Si) eutectic in different friction conditions were studied. Tribological tests were performed with two methods. According to one method, the samples were subjected to shaft–bush (counterface–material) tests by dry friction against ShKh15 steel employing an M-22M machine at a load of 20 N and a sliding speed of 1−6 m/sec. The other method involved quasistatic and dynamic sphere–plane tests with an effective load of 30 N employing a computer assisted tribology complex (CATC). The indenter materials were ShKh15 steel and Si₃N₄ ceramics. The tests were performed at a sliding speed of approximately 0.0147 m/sec in water. The intensity of linear and weight wear of the cast Ti−10Si−10Zr−1Sn sample with a superfine eutectic structure determined with the first method at the highest test speed (6 m/sec) was found to be 1.4 times higher than that of the Ti−9Si−7.6Zr alloys. The Ti–10Si–10Zr–1Sn alloy also showed the lowest wear resistance under quasistatic and dynamic loads with the second method, regardless of the indenter material (ShKh15 or Si₃N₄). Contrastingly to the previous data for cast irons and steels, the eutectic Ti−Si−Zr titanium alloys for the first time showed smaller wear under dynamic loading than under quasistatic loading. Thermomechanical treatment of the hypoeutectic Ti−9Si−7.6Zr alloy was established to increase its wear resistance by more than 1.6 times.