The effect of interacting defects on the HCF behavior of Al-Si-Mg aluminum alloys

Micro porosities generated by the casting process have a deleterious impact on the High Cycle Fatigue (HCF) behavior of the Al-Si-Mg alloys. The current paper presents a numerical study, based on Finite Element Analysis (FEA), aiming to evaluate the influence of complex micro pores on the aluminum alloys fatigue strength. Therefore, a 3D FE model, representing the porous aluminum, is implemented to determine the stress distribution around artificial defects with different distances between their edges. Work hardening due to the cyclic loading is considered by applying the Lemaitre-Chaboche model. The pore clustering phenomenon is investigated through an evaluation of the stress concentration around the defects, based on FE simulations. In order to characterize the impact of complex defect on the Al alloy HCF limit, a new definition of the equivalent defect was proposed. Comparisons between the developed approach and experimental investigations reported in the literature for AS7G06-T6, containing complex artificial porosities, are shown and discussed. (C) 2018 Elsevier B.V. All rights reserved.