Fragmentation of large grains in AZ31 magnesium alloy during ECAE via route A

An extruded AZ31 alloy which is not fully recrystallized and has numbers of elongated large grains with {0 0 0 2} 〈 1   1   2 ¯   0 〉 orientation was selected for ECAE. The results showed that, even after 8 pass extrusions via route A, there are still fragments of the large grains remaining in the sample. During ECAE, reorientation of the fragments takes place. The reorientation resulting in the basal plane gradually orienting perpendicular to the shear stress is responsible for the fragments remaining and for the non-efficiency of the refinement of the large grains.