Effect of Ti5Si3 on 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 Ti 5 Si 3 was prepared, and ultrahigh hardness (55.6 HRC) was achieved by solution aging treatment. The effects of Ti 5 Si 3 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 mm 3 N −1 m −1 to 3.93 × 10 −4 mm 3 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 Ti 5 Si 3 content leads to the increase of the friction pair force on the matrix, TiO 2 and SiO 2 wear debris are generated then fall off, both the oxidative wear and adhesive wear aggravated, which seriously impair the wear resistance of the alloy.