Surface hardness and corrosion behavior of laser surface-alloyed Ti6Al4V with copper

Laser surface alloying of Ti6Al4V with different Cu contents (6, 8, 13 and 17 wt%) was successfully achieved using a high-power diode laser. With a higher Cu content, the grain size of the laser surface-alloyed Ti6Al4V specimens became finer, with more intermetallic phases (IMPs) formed and the hardness increased up to 646 +/- 18 HV0.2. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were conducted to study the corrosion behavior of the laser surface-alloyed specimens in a 0.9 wt% NaCl solution at 37 degrees C. It was found that the specimen alloyed with 6 wt% Cu showed the mild micro-galvanic effect between CuTi2 and alpha-Ti. The specimen with 17 wt% Cu had the highest content of IMPs and possessed the lowest corrosion resistance due to the most significant micro-galvanic effect between the IMPs (cathode) and the alpha-T / beta-Ti matrix (anodes). With an appropriate Cu content, laser surface-alloyed Ti6Al4V can also act as hard and corrosion resistant components possessing a high anti-bacterial efficacy by virtue of Cu.

Automated summary

In this study, laser surface alloying of Ti6Al4V with different Cu contents was achieved using a high-power diode laser. It was found that higher Cu content resulted in finer grain size, more intermetallic phases (IMPs) formed, and increased hardness. Corrosion behavior study showed that the specimen alloyed with 6 wt% Cu exhibited mild micro-galvanic effect, while the specimen with 17 wt% Cu had the lowest corrosion resistance due to significant micro-galvanic effect between the IMPs and the matrix.