Effect of Mg-10Sr master alloy on grain refinement of AZ31 magnesium alloy

The effect of Mg-10Sr master alloy on the grain refinement of AZ31 magnesium alloy is investigated. The results indicate that the various Mg-10Sr master alloys (original, rolled, aged and remelted) can effectively refine the grains of AZ31 alloy. Furthermore, for a given 60-min melt holding time, the average grain size of AZ31 alloy treated with the various Mg-10Sr master alloys gradually decreases with the Sr amount increasing from 0.01 to 0.1%. In addition, for a given Mg-10Sr master alloy and 0.1% Sr, the average grain size of the AZ31 alloy treated for 20-min melt holding time is larger than that of the AZ31 alloy treated for 40, 60 or 80 min, and the effect of melt holding time on the average grain size becomes unobvious after 20 min. The grain refinement of AZ31 alloy treated with the various Mg-10Sr master alloys may be explained by the GRF (growth restriction factor) mechanism. (c) 2008 Elsevier B.V. All rights reserved.