A study on the solidification structure and tensile properties of Al-6.35wt% Si strip formed by strip casting

摘要

Al-6.35wt % Si strip was produced by the unequal-diameter twin-rolly strip caster to study relationship between the solidification structure and tensile properties. The solidification structure reveals two morphologies of the eutectic silicon paricles, namely granular and acicular. The granular silicon particles are residing in the columnar-dendrite zone and mixed zone at the regions near the upper and lower surfaces, and acicular silicon particles are in the equiaxed cell zone at the center region. To conduct room temperature tensile test, the strip was ground to vary relative thickness fraction of the different solidification zones. The tensile data thus obtained were adopted to calculate the flow stress of each solidification zone according to the rule of mixtures. The results indicate that these calculated values can be used to predict the flow stress of the strip. The current study also shows that the presence of acicular silicon particles in the equiaxed cell zone will reduce the tensile ductility.