Simulation of the corrosion-induced damage on aluminum alloy 2024 specimens with equivalent surface notches

Abstract

The effect of corrosion environment aggressiveness on the tensile mechanical properties degradation of AA2024-T3 was investigated. Tensile speci­­mens were pre-corroded for various exposure times to different corrosive solutions, i.e., exfoliation corrosion (EXCO) and 3.5 wt. % NaCl. Then they were tested mechanically. In non-corroded specimens, surface notches of vari­ous depths were machined to simulate the de­gra­dation of the tensile mechanical properties due to the presence of artificial surface defects. A mechanical model was developed to correlate the corrosion-induced tensile ductility degradation due to pitting and possible hydrogen embrittle­ment with the equivalent arti­fici­al­ly induced surface notches. The cases studied for this physical cor­re­la­tion were: a) EXCO exposure with artificial notches, b) EXCO with 3.5 wt.% NaCl ex­posure and c) 3.5 wt.% NaCl ex­posure with artificial notches. Higher corre­la­tion was noticed for short exposure times for all cases where the dominant de­gradation mechanism is slight pitting form­ation. It was found that 1 h EXCO ex­­posure is equivalent to 92 h exposure to NaCl solution re­gard­ing the tensile duc­tility degradation while 24 h EXCO exposure has the same effect on duc­til­ity decrease with a 240 μm surface notch or 4000 h exposure to NaCl solution.