Grain refinement behavior of potassium fluozirconate (K2ZrF6) salts mixture introduced into Mg–10Gd–3Y magnesium alloy

The influences of potassium fluozirconate (K2ZrF6) salts mixture (KSM) on the grain refinement, microstructure, mechanical properties and corrosion resistance of Mg–10Gd–3Y (GW103, wt.%) magnesium alloy were investigated. The results show that an addition of 8 wt.% KSM-2 (50 wt.% K2ZrF6–25 wt.% NaCl–25 wt.% KCl) provides the best combination of fine grain size and the lowest fraction of inclusions for GW103 alloy. The mechanical properties and corrosion resistance of GW103 alloy are improved by KSM-2 addition. The formation of Zr from the in situ reaction between Mg melt and K2ZrF6 is responsible for the refining mechanism of KSM. Compared with the Mg–30 wt.% Zr master alloy, the KSM refiner shows much longer fading time during smelting.