Evaluation of susceptibility to hydrogen embrittlement of 7075 aluminum alloy by hydrogen addition using flax-treatment method

Abstract

It is more difficult with aluminum alloys to investigate the effect of hydrogen on their mechanical properties than with steels because of their stable and protective oxide films, which act as a strong barrier for hydrogen penetration. In this study, after the flux-treatment, 707S-T6 alloy was subjected to thermal desorption spectroscopic (TDS) analysis and tensile test using the slow strain rate technique (SSRT) to establish a procedure for adding hydrogen to aluminum alloys and clarify the influence of hydrogen on their environmental embrittlement. The fluxtreatment consisted of applying a flux-solution for soldering on specimen surfaces and vaporizing water of the solution. These flux-treated specimens were exposed in a desiccator for various periods of time and then the solidified-flux and corrosion products were removed from the specimen surfaces before the TDS analysis and the tensile test. The experimental results revealed that hydrogen was absorbed into the alloy by the flux-treatment and the hydrogen content had a tendency to increase with increasing exposure time. Additionally, the fracture strain of tensile specimen decreased with exposure time, resulting in more severe embrittlement. Consequently, this flux-treatment method was considered to be an appropriate procedure for adding hydrogen to aluminum alloys and for evaluating their susceptibility to hydrogen embrittlement when combined with SSRT. © 2006 The Japan Institute of Metals.