Influence of vacuum annealing on surface morphology and structure of oxygen-implanted layer on Ti6Al4V alloy

Ti6Al4V was treated by oxygen plasma based ion implantation with -50 kV and 4. 5×10 ¹⁷ ions/cm ². Subsequent annealing in vacuum was applied to the implanted sample. The vacuum annealing leads to a large change for the surface morphology of the implanted sample. With increasing annealing temperature, dot and strip defects form first, afterwards the white areas appear at the surface of the implanted sample. After annealing at 500°C in vacuum, the surface roughness has not obvious change, but the annealing at 600°C results in a large increase in surface roughness. The vacuum annealing makes implanted oxygen run off the oxygen implanted layer and don't form titanium oxide phase.