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In this paper, the microstructural evolution, grain refinement and mechanical properties of as-cast Mg-6Zn-0.4Zr alloys with varying Sm contents(0, 2 wt.%, 4 wt.% and 6 wt.%) were investigated by using an optical microscope(OM), a scanning electron microscope(SEM) equipped with energy dispersive spectroscope(EDS), an X-ray diffractometer(XRD) and mechanical tests at room temperature, respectively. The experimental results indicated that the addition of Sm could obviously refine the as-cast grains, modify the eutectic morphology and affect the mechanical properties of the alloys. The main phases in Mg-6Zn-xSm-0.4Zr alloys included matrix α-Mg, Mg_2Zn_3, Mg_(41)Sm_5 and MgZ nS m. With Sm content increasing to 4%, the MgZ nS m phase was created, meanwhile, the morphology of some eutectic phases revealed apparently lamellar structure, which had a bad effect on the mechanical properties. In addition, the maximum values of ultimate tensile strength(UTS, 214 MPa) and elongation(EL, 7.42%) were simultaneously obtained from the alloy with 2% Sm. However, Sm addition had no obvious effects on the fracture behavior of the alloys, namely, the fracture pattern of Mg-6Zn-0.4Zr alloy belonged to inter-granular and brittle modes while the fracture regimes of all the Sm-containing alloys were dominated by the mixture of inter-granular and trans-granular modes.
In this paper, the microstructural evolution, grain refinement and mechanical properties of as-cast Mg-6Zn-0.4Zr alloys with varying Sm contents (0, 2 wt.%, 4 wt.% And 6 wt.%) Were investigated by using an optical microscope (OM) equipped with an energy dispersive spectroscope (EDS), an X-ray diffractometer (XRD) and mechanical tests at room temperature, respectively. The experimental results indicated that the addition of Sm could obviously refine the as-cast grains, modify the eutectic morphology and affect the mechanical properties of the alloys. The main phases in Mg-6Zn-xSm-0.4Zr alloys include matrix α-Mg, Mg_2Zn_3, Mg_41 Sm_5 and MgZ nS m. With Sm content increasing to 4%, the morphology of some eutectic phases revealed apparently lamellar structure, which had a bad effect on the mechanical properties. In addition, the maximum values of ultimate tensile strength (UTS, 214 MPa) and elongation (EL, 7.42%) we However, Sm addition had no obvious effects on the fracture behavior of the alloys, namely, the fracture pattern of Mg-6Zn-0.4Zr alloy belonged to inter-granular and brittle modes while the fracture regimes of all the Sm-containing alloys were dominated by the mixture of inter-granular and trans-granular modes.