Atomic Force Microscopy (AFM) images of (A,D) control, (B,E) RFGD-treated and (C,F) heat- treated Ti-6Al-4V samples for a (A-C) 10 × 10 μm scan area or a (D-F) 1 × 1 μm scan area. After applying a spatial high-pass filtering with a 200 nm cutoff to figures 1B and 1C, respectively, only the small-scale features of the RFGD-treated (G) and (H) heat treated samples remain.