Investigation of the Hydrogen Embrittlement Susceptibility of AA5083-H111 and AA6082-T6 Dissimilar Friction Stir Welds

Abstract

The present study focused on the evaluation of the hydrogen embrittlement susceptibility of dissimilar friction stir welds of AA5083-H111 and AA6082-T6 aluminum alloys. Electrochemical cathodic charging and slow strain rate tensile method were performed to investigate the embrittlement effect of diffused hydrogen cations into the polycrystalline matrices. The main embrittlement mechanisms were studied for applied current densities of 20, 50 and 80 mA/cm2 and duration of cathodic charging effect for 2 and 4 h. The slow strain rate tensile tests were performed with a strain rate of 2.4 × 10–4 s−1 in order to promote hydrogen migration effect to critical sites (deep traps). With the increment in applied current density from 20 to 80 mA/cm2, a severe reduction in ductility and a lower decrease in yield stress and ultimate tensile strength were observed. The fractured surfaces were characterized by increased volume fraction of embrittling features such as river patterns, quasi-cleavage facets and teardrop ridges.