(蘭州理工大學(xué) 省部共建有色金屬先進(jìn)加工與再利用國(guó)家重點(diǎn)實(shí)驗(yàn)室，蘭州 730050)
摘 要: 研究添加不同含量Zn對(duì)鑄態(tài)Mg-2Dy(摩爾分?jǐn)?shù)，%)合金顯微組織、時(shí)效行為和力學(xué)性能的影響。結(jié)果表明：Zn含量為0.5%和1%(摩爾分?jǐn)?shù))時(shí)，鑄態(tài)合金中分別析出片層狀具有18R類型長(zhǎng)周期有序(LPSO)結(jié)構(gòu)的Mg12ZnDy相和粗大的Mg3Zn3Dy2相；同時(shí)，Zn的添加細(xì)化了合金的晶粒；固溶處理后，LPSO相由18R類型轉(zhuǎn)變成沿晶內(nèi)分布的細(xì)條狀的14H類型，新的(Mg, Zn)xDy相形成，且Mg3Zn3Dy2相的體積分?jǐn)?shù)減小；添加0.5%Zn有效地增強(qiáng)了合金的時(shí)效硬化行為，提高了合金的室溫和200 ℃的拉伸強(qiáng)度。
關(guān)鍵字: Mg-Dy-Zn合金；顯微組織；時(shí)效行為；力學(xué)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
