(兰州理工大学 省部共建有色金属先进加工与再利用国家重点实验室，兰州 730050)
摘 要: 研究添加不同含量Zn对铸态Mg-2Dy(摩尔分数，%)合金显微组织、时效行为和力学性能的影响。结果表明：Zn含量为0.5%和1%(摩尔分数)时，铸态合金中分别析出片层状具有18R类型长周期有序(LPSO)结构的Mg12ZnDy相和粗大的Mg3Zn3Dy2相；同时，Zn的添加细化了合金的晶粒；固溶处理后，LPSO相由18R类型转变成沿晶内分布的细条状的14H类型，新的(Mg, Zn)xDy相形成，且Mg3Zn3Dy2相的体积分数减小；添加0.5%Zn有效地增强了合金的时效硬化行为，提高了合金的室温和200 ℃的拉伸强度。
关键字: Mg-Dy-Zn合金；显微组织；时效行为；力学性能
（State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,
Lanzhou University of Technology, Lanzhou 730050, China）
Abstract:The effects of Zn addition on the microstructure, aging behavior and mechanical properties of as-cast Mg-Dy alloy were investigated. The results show that the lamellar Mg12ZnDy phase with a 18R-type long period stacking ordered (LPSO) structure and coarse Mg3Zn3Dy2 phase precipitate in the alloy, respectively, when 0.5% and 1% (mole fraction) Zn are added. Simultaneously, the grains of the alloy are refined with increasing Zn content. After solution heat treatment, the 18R-type LPSO phase transforms to a strip-like 14H-type LPSO structure distributing in the grain interior. In addition, the (Mg, Zn)xDy phase forms and the volume fraction of Mg3Zn3Dy2 phase decreases. 0.5% Zn addition improves the aging behavior and strengthens the tensile strengths at room temperature and 200 ℃.
Key words: Mg-Dy-Zn alloy; microstructure; aging behavior; mechanical property
