Microstructure of Mg-Al-Zn Based Alloy Thick Ribbons Prepared by Melt Spinning

In this paper, the technology of rapidly solidified (RS) ribbons in Mg-3%Al-1%Zn-0.2%Mn alloy has been investigated using melt spinning technique with low speed. Cooling rate of the as-spun ribbons prepared at different wheel speed is estimated. Microstructures of as-spun ribbons are studied. The result indicates that the cooling rate of the as-spun ribbons with low speed is from 10~4 K/s to 10~5K/s. The grains of as-spun ribbons are smaller than the as-cast ingots'. The microstructure of the as-spun ribbon at 500 rpm along the cross section is uniform. While in the as-spun ribbon at 300 rpm, equiax crystals are found near the roller surface side, and near the unconfined flow surface, column crystals appear.