Effect of in-situ Al2Y particles on the as-cast/as-rolled microstructure and mechanical properties of AZ31 alloy

The Al2Y particle reinforced AZ31 alloy was prepared by adding Al and Y elements into AZ31 melt. The average dimension of these particles increased from 6.4 µm to 14.2 µm with the increase of Y and Al contents. TEM analysis proved the good interfacial bonding between the Al2Y particle and the matrix. The Al2Y particles resulted in the continuous grain refinement in the as-cast AZ31+xAl2Y (x=2, 4, 6 wt%) alloys. The as-rolled grains of Al2Y containing AZ31 alloys were also obviously refined compared with the as-rolled AZ31 alloy, which is attributed to the particle stimulated nucleation (PSN) during the hot rolling process. The as-cast/as-rolled mechanical properties were determined by the combination effects of the grain size and the Al2Y particles. Finer grains and small Al2Y particles contributed to the simultaneous improvement in strength and elongation. Furthermore, the texture of as-rolled AZ31 alloy was also weakened with Al2Y addition.