A master alloy including an alloy composition including magnesium (Mg) at a concentration of greater than or equal to about 1.00 wt. % to less than or equal to about 90 wt. %, boron (B) at a concentration of greater than or equal to about 0.01 wt. % to less than or equal to about 20 wt. %, and aluminum (Al) at a concentration of greater than or equal to about 0.1 wt. % to less than or equal to about 90 wt. %, wherein the alloy composition includes MgB