Effect of Ti₅Si₃on the wear properties of Ti-3Si-1.5Fe-1Mo titanium alloy with ultrahigh hardness

In this work, Ti-3Si-1.5Fe-1Mo titanium alloy reinforced with in-situ synthesized Ti5Si3 was prepared, and ultrahigh hardness (55.6 HRC) was achieved by solution aging treatment. The effects of Ti5Si3 on the friction and wear behavior of the alloy were investigated. Results show that the wear rate of the alloy after hot treatment increases from 3.51 × 10-4 mm3 N-1 m-1 to 3.93 × 10-4 mm3 N-1 m-1, yet the ultrahigh hardness alloy exhibits poor wear resistance. A series of the wear tracks characterizations and thermodynamical calculations were performed to elucidate its wear mechanism: during the reciprocating sliding, the reduction of the Ti5Si3 content leads to the increase of the friction pair force on the matrix, TiO2 and SiO2 wear debris are generated then fall off, both the oxidative wear and adhesive wear aggravated, which seriously impair the wear resistance of the alloy.