Effects of Al-Sr Master Alloys on the As-Cast Microstructure of the AZ31 Magnesium Alloys

The influence of Al-10.5%Sr master alloy, which is much cheaper than Mg-Sr master alloys, on the as-cast microstructure of the AZ31 alloy was investigated. The research results revealed that the Al-10.5%Sr master alloy produced obvious modification of the as-cast microstructure of the AZ31 alloy, and the modification efficiency increased with the holding time from 0min to 60min and the amount of Sr from 0.01% to 0.1%. Moreover, the results also showed that the Al-10.5%Sr master alloys of different states had different modification efficiency on the as-cast microstructure of the AZ31 alloy. The Al-10.5%Sr master alloys in extrusion deformation state and rapid solidification state had better modification efficiency than the Al-10.5%Sr master alloys received and in heat treatment state, which could be related to the microstructure of the Al-10.5%Sr master alloys with different states.