Experimental and numerical investigation of the residual yield strength of aluminium alloy EN AW-2024-T3 affected by artificially produced pitting corrosion

Abstract

Abstract. In this study, the behaviour of the residual yield strength of aluminium alloy EN AW-2024-T3 affected by the morphology and numbers of corrosion pits (defects) is presented. Since specific defect structures are not reproducible during experimental corrosion tests, metal sheets with different numbers of pits and pit shapes are produced using laser micro structuring. The defect structures are measured using laser scanning microscopy. To compare the stress states of the micro structured and real corroded metal sheets, FE-analysis is used. Afterwards, uniaxial tensile tests are carried out and critical defect parameters in terms of yield strength reduction of the investigated aluminium alloy are detected.

Nondestructive analysis of pitting corrosion characteristics on EN AW-2024-T3 using 3D optical pattern profilometry

“…For typical applications like FE-simulations of parts in service damaged by corrosion, the small deviation in shape is not significant, see, e.g. [11].…”

“…Since corrosion pits generally lead to an increasing local stress concentration [5,6,[11][12][13], they are the source of crack initiation [14] and hence the reduction of the functional fatigue life time of EN AW-2024-T3 [7,8,15]. But not only the fatigue life time reduces in the presence of local corrosion, but also the yield strength and ductility decreases [2,4,9,11,[16][17][18].…”

“…Other investigations using 3.5% NaCl solution with additives such as hydrogen peroxide [7,8] and even 3 M NaCl electrolyte solutions with an applied voltage of 0.63 V [5,6] show pitting corrosion as well as intergranular corrosion, exhibiting pit depths in the range 200– 400 [8], respectively, 400– 600 [5]. Since corrosion pits generally lead to an increasing local stress concentration [5,6,11–13], they are the source of crack initiation [14] and hence the reduction of the functional fatigue life time of EN AW-2024-T3 [7,8,15]. But not only the fatigue life time reduces in the presence of local corrosion, but also the yield strength and ductility decreases [2,4,9,11,16–18].…”