A new cast Mg-Y-Sm-Zn-Zr alloy with high hardness

The microstructure and aging precipitates of a new cast Mg-Y-Sm-Zn-Zr alloy were investigated. The results showed that eutectic phase forming in solidification process was proved to be (Mg,Zn)3(Y,Sm). The alloy exhibited high hardness (maximum value of 148 HV), which is higher in comparison with other high rare-earth Mg alloy. The aging precipitate β′ is thermally stable at 200 °C for the crystal structure of β′ kept unchanged in the whole aging process.