Dry sliding wear mechanisms in a Ti50Ni47Fe3 intermetallic alloy

Abstract

Ti50Ni47Fe3 intermetallic alloy with a B2 structure can be strengthened by means of a thermomechanical treatment to obtain a combination of high strength and high ductility. The strengthened Ti50Ni47Fe3 alloy with yield strength of 830 MPa and tensile ductility of 15% was tested for dry sliding wear against a SAE 52100 bearing steel using a block on ring wear test configuration. The Ti50Ni47Fe3 alloy demonstrated excellent wear resistance against SAE 52100 steel in the load range 2–400 N investigated in this study. The wear rates of the Ti50Ni47Fe3 were found to be 2–5% of that of the SAE 52100 steel despite the lower hardness of the alloy. The metallographic characterization of the worn surfaces indicated that a tribolayer containing mainly iron oxides formed on the wear tracks of the intermetallic. Plastic deformation and mechanical mixing in the subsurface material produced a hardened layer with finger like morphology beneath the oxide layer. The wear resistance of the Ti50Ni47Fe3 alloy is discussed in terms of the subsurface work hardening and mechanically mixed tribolayer formation on the worn surfaces.