Comparison of Corrosion Behavior of Friction Stir Welded (FSW) of Ti-6Al-4V Titanium Alloy

Fusion welding can deteriorate the corrosion feature of Ti-6Al-4V alloys due to the existence of some metallurgical defenses such as discontinuity, Oxygen and Nitrogen absorption and creation of pore holes. By employing friction stir welding, the appropriate corrosion resistance could be reachable. In current research, Ti-6Al-4V with thickness of 3mm was used. Structural characterize of welded zone were evaluated by scanning electron microscopy, equipped by EDS microanalyses XRay diffractometry (XRD). Corrosion behavior of fabricated specimen was investigated by means of potentiostat (EG & G 273A). The SEM micrographs and EDS results confirmed that ununiformity chemical composition and various types of metallurgical phase were formed, which caused the corrosion resistance of transition zone declined as compared to the stirzone and the base metal zone has the highest value of corrosion resistance. It was found that the stir zone contain the typical Alpha () phase plus recrystallization Beta () phase along with tungsten debris while transition zone contain equiaxed and bimodal lamellae structure. The corresponding current density for stir zone, transition zone and base metal were 3.126, 1.532, 0.530 μA respectively, while obtained potential for those mentioned zones were -240, -226 and -172 mV respectively.