Comparison of Corrosion properties of Laser & TIG welded Ti-5Al-2.5Sn Alloy

Abstract

The electrochemical corrosion behavior of Laser and TIG welded Ti-5Al-2.5Sn alloy was studied in 3.5% NaCl solution using potentiodynamic polarization. Comparisons between corrosion resistance of laser and TIG welded samples were made on the basis of corrosion potential (Ecorr) and current density (icorr) values obtained from the polarization curves. XRD and micro-structural analysis was done to determine the phase changes produced by these welding techniques. Micro-hardness was also evaluated using a Vickers Hardness Tester. Based on the Ecorr and icorr values, it was found that laser welded samples showed a higher corrosion resistance as compared to the TIG welded samples. XRD and micro-structural analysis showed the formation of α′ martensitic structure without prior β grains in case of laser welded samples and needle like α′ martensitic structure with equiaxed prior β grains in case of TIG welded samples. The hardness values observed were higher in case of laser welded samples.