Fretting corrosion experiments were performed on Ti-6Al-4V similar metal, pin-on-flat fretting couples. Relative displacement amplitudes between the fretting specimens were directly measured using LVDT's. The effect of varying the amplitude of the fretting displacement on the fretting-enhanced dissolution behavior was determined using atomic absorption spectrophotometry and measurements of open circuit potential and potentiostatic fretting currents.
The potential and current measurements exhibited two distinct stages with more active values recorded during the first stage followed by a noble-direction transition. Analysis of cumulative soluble dissolution product also revealed two-stage behavior with higher initial dissolution rates and subsequent transitions to reduced release rates. The number of fretting cycles to the dissolution rate, current, and potential transitions increased with the displacement amplitude. Scanning electron micrographs revealed the accumulation of wear debris within the fretting contacts. It is suggested that the observed reductions with time in fretting-enhanced corrosion are related to a protective mechanism associated with the accumulated wear particles. Experimental results demonstrate the importance of minimizing fretting displacements in implant designs containing Ti-6Al-4V similar metal, fretting-prone contacts.