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pISSN : 1598-706X / eISSN : 2288-8381


한국주조공학회지 (41권5호 434-444)

Effects of Damage Evolution of Eutectic Si Particle and Microporosity to Tensile Property of Al-xSi Alloys

Al-xSi합금의 인장특성에 미치는 공정 Si입자의 파단과 미소기공율의 영향

ChoongDo Lee†

인하공업전문대학 금속재료과



This study investigated the overall dependence of the tensile properties of Al-Si alloys on the distribution aspect of a eutectic Si particle in terms of defect susceptibility to the effective void area fraction, referring to the sum of pre-existing microvoids and the damage evolution of the Si particle. The network morphology of as-cast Al-xSi (x=2,5,8,11) alloys was modified to a granular type via a T4 treatment, after which a computational topography (CT) analysis and scanning electron microscope (SEM) observations were utilized to evaluate the size and distribution of the microvoids. The CT and SEM analyses indicated that the main cracks grow along local regions that possess the highest porosity level. The local plastic deformation around the microvoids and the distribution aspect of the microvoids induced a practical difference between the iso-volumetric CT measurement and the SEM fractography outcomes. The results demonstrated that the overall dependence of the ultimate tensile strength (UTS) and elongation on the effective void area fraction is more sensitive to the variation of the area fraction of the Si particle in the network morphology than in the granular type; this is due to the sequential damage evolution of the neighboring Si particles in the eutectic Si colony.


Tensile property, Aluminum alloy, Microporosity, Defect susceptibility and Eutectic Si particle