The effect of laser shock processing on the anti-corrosion performance of LENS-Fabricated Ti-6Al-4V alloy

Abstract

Titanium alloys are prone to increased oxidation rates when exposed to higher temperatures during application. As a result, the components suffer mechanical failure due to the formation of the alpha-case layer at 500 °C. To improve its corrosion and oxidation properties, and ultimately its mechanical performance, it is necessary to modify its surface properties. In this study, a LENS 3D-printing system was used to fabricate titanium alloy sample coupons, while surface treatment was performed using laser shock processing (LSP) to improve the surface properties. The characterisation of the samples was performed to establish a basis for the corrosion behaviour of the 3D-printed material and the effect of LSP treatment on the rate of corrosion. The samples fabricated at the moderate laser energy density of 249 J/mm3 showed the best-performing properties as the microstructures that evolved showed elevated hardness profiles, which were associated with material property improvements such as high strength and corrosion resistance. After subjecting the samples to LSP treatment, the properties of the LENS samples showed a further improvement in corrosion resistance.