Water droplet erosion of laser surface treated Ti6A14V

Abstract

The work reports on the effect of laser surface treatments on the water droplet erosion resistance of a commercial alloy of nominal composition Ti6A14V. Use is made of a continuous wave CO 2 laser to melt the Ti6A14V in both inert and dilute nitrogen atmospheres. The gas composition of the atmosphere is set at either 100% Ar, 90% Ar + 10% N 2 or 80% Ar + 20% N 2 by volume. The successive intertrack overlap is set at either 50% or 75% of the surface width of a single melt track. The cumulative mass loss during water droplet erosion of the laser surface melted material decreases substantially relative to the untreated material for all processing conditions examined. The enhanced erosion resistance is attributed to increases in the surface layer microhardness as well as the resistance of the martensitic microstructure to the hydraulic penetration mechanism of erosion. The benefits of nitrogen alloying over surface melting in an inert environment are not substantial, but this may be attributed to pre-existing micro-cracks in the nitrogen alloyed surface layers.