Laser assisted nitriding of Ti-6Al-4V alloy: Metallurgical and electrochemical properties

The surface properties of Ti-6Al-4V alloy, such as wear resistance, are ina dequate for many applications. To improve the surface properties of the all oy, many techniques have been considered. One of the promising techniques i s to form a nitride layer on the surface of the workpiece by a laser beam. In the present study. laser assisted nitriding of the Ti-6Al-4V alloy surfa ce is carried out under a nitrogen gas flow environment. A CO2 laser is use d to irradiate the Ti-6Al-4V alloy surface while nitrogen is introduced co- axially with the laser beam onto the workpiece surface. The resulting surfa ce cross section is examined metallurgically. SEM and XRD were carried out for material characterization. The study is extended to include the electro chemical response of the resulting surfaces. The surface morphology of the electrochemically treated workpieces are examined. It is found that in the laser treated region dendritic structures occur and TiN forms in the surfac e vicinity. The density of pit formation at the surface of the treated regi on reduces considerably.