Study on Laser-Induced Oxidation of Ti6Al4V Alloy Under Two Different Reactive Atmospheres

Abstract

The oxidation behavior of Ti6Al4V titanium alloy under laser irradiation in atmospheric and oxygen-assisted conditions was studied. A nanosecond-pulsed Yb: glass fiber laser was used. The thickness of oxide layer, microstructure, and phase composition of the material after laser irradiation were investigated. The characterization of the surface and subsurface microstructure, as well as the cross-sectional morphology were performed using scanning electron microscopy (SEM). The phase identification was performed using X-ray diffraction (XRD). The combined effects of accumulated laser fluence and reactive atmosphere on the oxidation behavior of Ti6Al4V were also studied in detail. With an increase in accumulated laser fluence, a porous and easily removable oxide layer gradually formed on the surface, whereas a compact oxide layer was also formed. At high accumulated laser fluence, the thickness of the porous oxide layer increased dramatically, while the change of thickness of compact oxide layer was not obvious. The reactive atmosphere also had a significant influence on the microstructure of the surface and subsurface layers. SEM and XRD results revealed existence of strong oxidation reactions that underwent in the condition of assisted oxygen delivery at a fixed accumulated laser fluence. The oxide layer was composed mainly of anatase and rutile titanium oxides.