Effects of calcium, samarium addition on microstructure and mechanical properties of AZ61 magnesium alloy

The microstructure and mechanical properties of AZ61 magnesium alloy with Ca, Sm addition were investigated. The results showed that the addition of 0.5 wt.% Ca reduced the quantity of Mg17Al12 phase, and formed a new Al4Ca phase which is reticular in AZ61 alloy. With the addition of Ca and Sm, the microstructure was further refined and new Al-Sm rich phases were formed in AZ61 alloy with 0.6 wt.%–1.5 wt.% Sm addition, the TEM analysis confirmed that they were Al2Sm and Al4Sm. Tensile tests showed that 1.0 wt.% Sm addition contributed to the formation of the Al2Sm and Al4Sm and the improvement in the ambient strength, i.e., an ultimate tensile strength of 327 MPa and an elongation of 10.1%. However, excessive Sm addition led to the coarsening of Al2Sm and Al4Sm phases, thus resulted in the decline of strength and plasticity.

SEM images of as-cast alloys AZ61 (a) and AZ61-0.5Ca-xSm (x=0, 0.6, 1.0, 1.5) (b–e)Figure optionsDownload as PowerPoint slide