This work aims to present a perspective for porosity formation in three different alloys: A356,A413 and A380.1 by taking into account the addition of Al-B grain refiners: AlTi5B1 and Al3B. The directionalsolidification method was used, and microstructural changes of the alloys and its correlation with porosityformation were investigated. Pore size, number of pores, average pore length and distribution of pores werestatistically analyzed. Also, external shrinkage was examined, and the volume of external shrinkage wascalculated. It was found that there was a relationship between external shrinkage and the size and number ofpores. As the size and number of pores internally decrease, external shrinkage increases. Additionally, porosityis decreased in all the three Al-Si alloys when Al-B grain refiners are used. The distribution of pore diameters islow when AlTi5B1 is used. Grain refiners have a different effect on porosity formation of Al-Si alloys with regardto their solidification morphology.
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