The effect of cryogenic CO2 cooling on corrosion behaviour of friction stir welded AA2024-T351

Abstract

Cryogenic cooling with CO₂ was applied during friction stir welding of AA2024-T351 in order to reduce the temperature increase during welding, and thus improve the corrosion resistance of the weld. The effect of cryogenic cooling on corrosion susceptibility was investigated with gel visualisation, immersion tests and local electrochemical measurements. The most susceptible area for both uncooled and cooled welds was in the heat-affected zone (HAZ) region, which showed intergranular attack. Cryogenic cooling had no detectable influence on the degree of anodic reactivity in the weld region. However, it did decrease the width of the reactive HAZ.