Pitting corrosion studies on Ti6Al4V alloy weldments in marine environment

摘要

Titanium and its alloys are widely used owing to their high strength-to-weight ratio, good tensile strength, and resistance to corrosion. The Ti6Al4V alloy is called the workhorse among the titanium alloys owing to its wide application. Even though the Ti6Al4V alloy is immune to corrosion, improper welding conditions lead to contamination, making the weldments prone to stress corrosion cracking (SCC). These weldments are susceptible to SCC if they show sensitivity to pitting. This study examines the effect of welding conditions on the pitting corrosion behavior of 3 mm thick plates of Ti6Al4V alloy. The Ti6Al4V weldments were fabricated using fusion welding methods, namely, the gas tungsten arc welding (GTAW) and laser beam welding (LBW) techniques. The pitting corrosion studies were carried out by a potentiodynamic polarization technique, using non-deaerated 3.5 NaCl solution of pH 7, to create a marine corrosion environment. The pitting corrosion studies yielded good results as there was corrosion resistance in weldments fabricated under controlled conditions.