Comparative Study of Corrosion, Mechanical and Electrical Characteristics of Tungsten inert Gas and Friction Stir Welded Joints

Aluminium alloys are welded using both tungsten inert gas welding (TIG) and friction stir welding (FSW). FSW doesn’t need any filler material and shielding gas which results in reduced degradation of the environment. In the present study, joints with FSW and TIG processes were compared in terms of microstructure, corrosion resistance, mechanical, and electrical properties. With a microstructural study, the average grain size of various regions was determined. Coarse grain increases the rate of exfoliation corrosion. The fine grain structure in the FSW stir zone increases the hardness. The coarse grains are a prerequisite for enhanced electrical conductivity. The coarse grains in the heat-affected zone and thermomechanically affected zones of FSW joints result in increased electrical conductivity. In the case of friction stir welded joints, there is an inverse relationship between hardness and electrical conductivity. As hardness increases, electrical conductivity decreases, and vice versa. Hence, in the case of FSW hardness test can be substituted by an electrical conductivity test. In the case of TIG, no relation was found between hardness and electrical conductivity. High Silicon content at the weld region of TIG significantly reduces electrical conductivity