(A) Variation of friction coefficient with time for Ti-6Al-4V when sliding against a 100Cr6 steel ball. (B) Shows the wear track at the end of the tests. (C) Is an enlargement of (B). Identical result was obtained for all the specimens tested (whatever the counterpart surface, alumina or 100Cr6 steel) except the one implanted at the highest dose of 2 × 10¹⁷ N⁺/cm² when sliding against an alumina ball. In this case, no wear was detected.