The effect of the selection of the secondary solidification phase on the mechanical properties of the Mg-Sn-Zn and Mg-Sn-Zn-Al alloy rolled sheets has been investigated in the present study. The as-cast microstructure of Mg-7Sn-2Zn (in wt.%) alloy consists of α-Mg dendrite and interdendritic Mg 2Sn and MgZn2 phases, while that of Mg-7Sn-5Zn-2Al alloy consists of α-Mg dendrite and interdendritic Mg2Sn and icosahedral (I-) phases. The micron scale interdendritic I-phase in the as-cast Mg-7Sn-5Zn-2Al alloy dissolves into the matrix during homogenizing treatment, and appears again in the α-Mg matrix as 0.1-0.5 μm size fine spherical precipitates after rolling process. As a result, the Mg-7Sn-5Zn-2Al alloy exhibits high yield strength of 318 MPa in as-rolled state. The high level of strength is attributed to the presence of finely distributed Mg2Sn and I-phase particles embedded in the α-Mg matrix.
All Science Journal Classification (ASJC) codes
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry