Corrosion Behavior of a Laser Surface-Treated Alpha–Beta 6/4 Titanium Alloy

Laser surface treatment of Ti–6Al–4V alloy was carried out by means of a Q-switched Nd:YAG laser. Different laser exposure times were attempted aiming to get the optimal conditions for promising mechanical and electrochemical properties. The microstructure was examined using scanning electron microscopy attached with energy dispersive spectrometer for chemical composition analysis, and the electrochemical behavior of the treated samples was tested by means of polarization test. The corrosion resistance was investigated in Ringer´s solution. The results were compared with those obtained from untreated alloys tested in same conditions. Laser treatment produced a transformed layer with acicular martensite α′-Ti as a result of the recrystallization of the fully lamellar α + β microstructure of the substrate. The results indicate that ultra-short pulses (in nanosecond scale) from Nd:YAG laser effectively enhanced the corrosion resistance of this alloy in acidic media (Ringer’ s solution). A notable enhancement of hardness was reached as well.