Analysis of Ti-6Al-4V adhesion to AISI 52100 steel and TiN during unlubricated sliding contact

The adhesion mechanisms of Ti-6Al-4V alloy to AISI 52100 steel and TiN nitride coating under unlubricated sliding condition were studied using analytical microscopy techniques. Ti-6Al-4V was transferred to both counterfaces at the early stages of contact. The transferred layer had an amorphous structure in which nanocrystalline and polycrystalline oxides were embedded. High resolution TEM (HRTEM) and fast Fourier transform (FFT) investigations revealed the presence of nanocrystalline TiO (C2/m) at the steel/transfer layer interface; however, α-titanium P6/mmm was detected at the TiN/transfer layer interface. The different friction behaviors of the steel and TiN were attributed to this observation. The adhesion behavior of Ti-6Al-4V to steel and TiN counterface materials was related to the misfit between α-titanium and counterface crystal structures.