(a–d) SEM images of surface microhexagon structures on Ti6Al4V samples at different side length of hexagon: 150 μm, 200 μm, 250 μm, and 300 μm, respectively, fabricated by laser pulses at same influence of 2000 J/cm² in the moving speed of 100 mm/min (Scale bar is 200 μm in the subfigures); (e–h) SEM images of surface morphology of Ti-6Al-4V samples with microhexagon structures after chemistry surface treatment at different side length of hexagon: 150 μm, 200 μm, 250 μm, and 300 μm, respectively (scale bar is 200 μm in the subfigures); (i) SEM image of surface morphology within microhexagon in (f); (j) SEM image of surface morphology in the high power microscopic view of (i); (k) SEM image of surface morphology in the channel between microhexagons in (f); (l) three-dimensional morphology of (f).66