Effect of laser surface melting on superficial morphology and properties of the electrochemical polishing Ti6Al4V alloy

Abstract

Titanium alloy is a typically difficult-to-process material, and its surface state significantly impacts its applications in aerospace, ships, and other fields. To obtain high-quality surface, laser surface melting and electrochemical polishing (LSM-ECP) combined processing was presented to polish Ti6Al4V in this study. The effects of laser surface melting (LSM) on the electrochemical polishing (ECP) surface morphology and properties of Ti6Al4V alloy (LSM-ECP) was studied. The research includes microstructure evolution, surface phase and element change, microhardness, and surface corrosion resistance. The results showed that the LSM-ECP surface roughness was further reduced by 73.8%–168 nm. LSM-ECP can partially remove the remelted layer, and the generated metal oxides such as TiO2, Ti2O3, TiO, Al2O3. and other metal oxides help protect the surface of the specimen, reduce corrosion, and the surface hardness and corrosion resistance of the substrate was improved. It can be concluded that grain refinement, a large number of needle-shaped α′+β phases and dislocatiaon in the LSM Ti6Al4V alloy can provide more numbers of corrosion of grain boundaries, the oxide layer and low roughness during the ECP process. The electrode response of LSM-ECP is faster than that of direct ECP of the substrate surface, better polishing result is obtained in a shorter time.

Keywords

• Laser surface melting
• Electrochemical polishing
• Surface roughness
• Surface properties
• Polishing mechanism