The impact of defect morphology, defect size, and SDAS on the HCF response of A356-T6 alloy

This paper aims to investigate the influence of defect morphology, defect size, and SDAS on the fatigue behavior of A356-T6 aluminum alloy. A 3D finite element analysis for specimens containing different pore morphologies—(i) spherical pore, (ii) elliptical pore, and (iii) complex pore—was implemented. The Chaboche kinematic hardening model embedded in Abaqus is used to characterize the material response during cyclic loading. Kitagawa diagrams for defective A356-T6 are simulated using the defect stress gradient (DSG) approach. A good agreement is found between experimental and numerical results for predicting fatigue limit in the case of spherical defects. The impact of defect morphology on the fatigue resistance is clearly demonstrated. This paper shows that aluminum fatigue resistance is strongly dependent on the defect size, SDAS, and the defect morphology. Therefore, a mathematical model that takes into account the impact of these three parameters is developed using response surface (RS) approach to predict fatigue limit of porous aluminum alloy. Moreover, the effects of defect morphology, defect size, and SDAS on fatigue response and their interactions under fully reserved tensile loading are investigated.