Tribological and Mechanical Properties of Fe/Ti Multilayered films

A 900 Å as-deposited multilayered structure of alternating Fe and Ti on hardened tool steel has been examined for tribological and mechanical properties. The multilayer in contact with a 52100 steel ball counter surface possessed a 0.16 friction coefficient and showed good wear character after 1000 cycles in pin-on-disk experiments. Nanoindentation experiments show a 20 % increase in hardness for material in the wear track. Electron microscopy data suggests that the as-deposited bcc-Fe plus hcp-Ti multilayer composite transforms to a nanocrystalline alloy plus bcc-Fe by solid state reaction during pin-on-disk friction and wear test. The low friction observed in these surface films is attributed to the formation of a hard nanocrystalline alloy and improved interlayer and film/substrate adhesion which result during solid state reaction.