Reciprocating Wear Performance and Interfacial Microstructure of a TiC–Ni2AlTi Cermet

Abstract

Wear performance of a near equi-volume TiC–Ni2AlTi cermet with minor NiAl was evaluated by reciprocal sliding against Si3N4 balls. Both coefficient of friction (COF) and specific wear rate (SWR) decrease with the applied load in the range from 5 to 20 N, reaching minimums of 0.34 and 2.2 × 10−6 mm3/Nm, respectively, at 20 N. To understand the novel wear resistance, interfacial microstructure was investigated. As indicated by high resolution transmission electron microscopy observations, the interfaces are either coherent (TiC/NiAl and Ni2AlTi/NiAl) or semi-coherent (TiC/Ni2AlTi). Depending on the grain size of Ni2AlTi, two types of TiC/Ni2AlTi interface were observed. For the micrometer or sub-micrometer sized Ni2AlTi grains, the orientation relationship (OR) is (111) TiC ∥ (220) Ni2AlTi, [1 $$\bar{1}$$ 0] TiC ∥ [1 $$\bar{1}$$ 0] Ni2AlTi, while for the Ni2AlTi grains in tens of nanometers, the OR is (020) TiC ∥ (002) Ni2AlTi, [101] TiC ∥ [010] Ni2AlTi. The strongly bonded coherent and semi-coherent interfaces impede the failure of the heterophase boundaries, which accounts for the excellent wear resistance of the newly prepared cermet.