THE EFFECT OF HYDROGEN DURING STRESS CORROSION CRACKING AND CORROSION FATIGUE OF Al-Li-Cu ALLOYS IN 3.5 % NaCl SOLUTIONS

Abstract
Stress corrosion cracking and corrosion fatigue tests at imposed strain rate are conducted on an industrial Al-Li-Cu alloy in a 3.5 % NaCl solution at imposed potential. In the condition of the tests and for short fatigue lifetimes, the anodic dissolution is shown to play the predominant role during corrosion-fatigue at free corrosion potential. Nevertheless a marked hydrogen embrittlement is observed at cathodic potentials during corrosion fatigue of specimens containing superficial microcracks. These observations are discussed to compare the susceptibility to hydrogen embrittlement of the Al-Li-Cu alloys and of conventional Al-Zn-Mg alloys during stress corrosion and corrosion-fatigue tests.