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

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. [GRAPHICS] .