Effects of Hf content on nanotubular structure of Ti-29Nb-xHf ternary alloys

The Ti-29Nb-xHf alloys had an equiaxed grain structure with α″ + β phases, and the α″ phase disappeared with an increase in the Hf content. The Ti-29Nb-15Hf alloy showed higher intensity β-phase peaks in the XRD patterns compared to Ti-29Nb-3Hf and Ti-29Nb-7Hf alloys. The average length of the nanotubes increased and the nanotubes became highly ordered as the Hf content increased. The contact angles of the surface with the nanotubes were lower than those of surfaces without nanotubes.