Grain Refining Mechanism of Al and Zn Element for Magnesium Alloys

Grain refining mechanism of Al and Zn element for magnesium alloys was investigated through analyzing crystal extricating phenomenon, and a new mathematical model, which could be used to evaluate grain refining ability of extricating crystals, was developed. Results show that grain refining ability of extricating crystals in Mg-Al alloys was higher than in Mg-Zn alloys with the same solute content; the higher the solute content, the larger the difference of grain refining ability of extricating crystals in the two alloys. It is suggested that the difference of grain refining ability of extricating crystals may be the main reason for smaller grains of Mg-Al alloys than Mg-Zn alloys.