Laser induced periodic surface structure on titanium alloy and its effect on microstructure refinement and corrosion behavior

Abstract

Laser induced periodic surface structure (LIPSS) is known to enhance optical properties and adhesion behavior of various materials, but its effect on microstructural evolution and corrosion properties of metallic alloys is not well understood. An effort has been made to study the effect of LIPSS following picosecond laser processing on microstructural evolution and corrosion behavior of Ti6Al4V alloy. The results of electron backscatter diffraction(EBSD) and transmission electron microscope(TEM) indicate that grains at the surface have been refined significantly, while gradient dislocation structure including dislocation cell structure at the top surface and dislocation tangle with high density at the sub-surface has been formed with the increasing depth. The study of polarization suggests that the corrosion resistance increases significantly, which is mainly due to low interface energy of the dislocation cell structure.