中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
Vol. 20 No. 7 July 2010 |
(Key Laboratory for Anisotropy and Texture of Materials of Ministry of Education,
Northeastern University, Shenyang 110004, China)
Abstract:The microstructure and mechanical properties of Mg-xSn (x=3, 7 and 14, mass fraction, %) alloys extruded indirectly at 300 ˚C were investigated by means of optical microscopy, scanning electron microscopy and tensile test. The grain size of the α-Mg matrix decreases from 220, 160 and 93 μm after the homogenization treatment to 28, 3 and 16 μm in the three alloys after extrusion, respectively. The results show that the grain refinement is most remarkable in the as-extruded Mg-7Sn alloy. At the same time, the amount of the Mg2Sn particles remarkably increases in the Mg-7Sn alloy with very uniform distribution in the α-Mg matrix. In contrast, the Mg2Sn phase inherited from the solidification with a large size is mainly distributed along grain boundary in the Mg-14Sn alloy. The tensile tests at room temperature show that the ultimate tensile strength of the as-extruded Mg-7Sn alloy is the highest, i.e., 255 MPa, increased by 120% as compared with that of as-cast samples.
Key words: Mg-Sn alloy; extrusion; tensile property; microstructure