Efficacy of borides in grain refining Al-Si alloys dataset

The grain refining efficacy of titanium, aluminium and niobium borides, as well as niobium aluminides, introduced via commercial and lab made master alloys on Al-Si alloys was investigated. Significant grain refinement is achieved via the introduction of these heterogeneous nuclei regardless of their nature, stoichiometry of the master alloy, and addition rate. However, the grain refinement is affected by variable such as contact time and cooling rate. In the case of borides, the chemical inoculation efficiency is greatly affected by their thermodynamic stability in molten Al-Si alloys. Conversely, the grain refining potency of properitectic Al₃Nb remains unaffected. The underlying grain refining mechanism was finally investigated using current model based on the growth restriction factor <i>Q</i> to simultaneously consider the effect of nucleants potency and alloy chemistry. Among Ti-, Al- and Nb-based borides with similar particle size and distribution, the latter are the most efficient to grain refine Al-Si alloys.