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 embrittle¬ment with the equivalent arti¬fici¬al¬ly induced surface notches. The cases studied for this physical cor¬re¬la¬tion were: a) EXCO exposure with artificial notches, b) EXCO with 3.5 wt.% NaCl ex¬posure and c) 3.5 wt.% NaCl ex¬posure with artificial notches. Higher corre¬la¬tion was noticed for short exposure times for all cases where the dominant de-gradation mechanism is slight pitting form¬ation. It was found that 1 h EXCO ex¬¬posure is equivalent to 92 h exposure to NaCl solution re¬gard¬ing the tensile duc¬tility degradation while 24 h EXCO exposure has the same effect on duc¬til¬ity decrease with a 240 �m surface notch or 4000 h exposure to NaCl solution

Keywords

• corrosion
• notches
• mechanical properties
• aluminum alloy