عنوان مقاله [English]
In the current study, the effects of bismuth and T6-heat treatment on the microstructural and tensile properties of SiC-reinforced Al-Si alloy (LM13) have been investigated. The alloys were subjected to the solution and ageing treatment to investigate its effect on the characteristics of eutectic silicon particles and tensile properties. The microstructures of specimens were examined by using optical and scanning electron microscopy. According to microstructural results, the most improvement in the modification of eutectic silicon phase was achieved by the addition of 1 wt. % bismuth. On the other hand, applying T6-heat treatment spherodize the silicon particles and thus modify the microstructure of the alloys. Adding bismuth and applying heat treatment simultaneously intensify the modification effect of each of them. The tensile testing was employed to measure the quality index (QI) of the alloys for evaluating the modification efficiency of the alloy with different bismuth contents. The reduction in both tensile strength and ductility after addition of higher contents of bismuth was found to be due to the formation of bismuth–rich phases in the microstructure. The results of fractography showed that bismuth in its optimum level changed the fracture mode from brittle to ductile. This is due to the reduction in dimples size.
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