Effects of samarium addition on as-cast microstructure, grain refinement and mechanical properties of Mg-6Zn-0.4Zr magnesium alloy  

作　　者：张玉 黄晓锋 李雅 马振铎 马颖 郝远 

机构地区：[1]State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China

出　　处：《Journal of Rare Earths》2017年第5期494-502,共9页稀土学报（英文版）

基　　金：Project supported by the National Nature Science Foundations of China(51464032);the National Basic Research Program of China(2010CB635106)

摘　　要：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, Mg2Zn3, Mg（41）Sm5 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）, 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, Mg2Zn3, Mg（41）Sm5 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.

关 键 词：refinement magnesium eutectic tensile lamellar ultimate granular grains precipitate dispersive 

分 类 号：TG146.22[一般工业技术—材料科学与工程]