Tribo-behavioural transition of Ti6Al4V as a function of sliding velocity and load under dry sliding conditions

Abstract

In this work, the dry sliding wear characteristics of Ti6Al4V (Ti64) – EN31 (steel) tribo-pair at incremental sliding velocity (SV, 0.838–1.466 ms_-1) and load (L, 50–100 N) conditions are elucidated. As evident, specific wear rate (SWR) and coefficient of friction (CoF) increases and decreases, respectively with load and SV. The wear response of Ti64 undergoes a transition from composite type (oxidative and metallic) to delamination. The evolved oxides, viz. TiO and Ti₈O₁₅ were majorly in the form of free particulates. At low SV (0.838–1.047 ms_-1) and low load (50–70 N), the movable particulates can activate a separation effect limiting the damage due to wear. During severe sliding (SV = 1.257–1.466 ms_-1 and L = 70–100 N), the combined influence of frictional heating instigated thermal softening, and the formation/retainment of hard-coarse particulates at the interaction zone causes perforation into the substratum, assisting in spalling.