(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083；2. 北京航空航天大學(xué) 材料科學(xué)與工程學(xué)院, 北京100083；3. 華中科技大學(xué) 材料科學(xué)與工程學(xué)院，武漢430074)
摘 要: 用Gleeble−1500熱/力模擬機(jī)研究Mg-9Y-3Zn-0.5Zr鎂合金在應(yīng)變速率為0.001~0.1 /s，變形溫度為543~743 K下的熱變形行為，分析實(shí)驗(yàn)合金在高溫變形時(shí)的流變應(yīng)力和應(yīng)變速率及溫度之間的關(guān)系，計(jì)算變形激活能和應(yīng)力指數(shù)，并討論熱壓縮過程中的組織變化。結(jié)果表明：在同一變形溫度下，實(shí)驗(yàn)合金的真應(yīng)力水平隨應(yīng)變速率的增加而增加，隨溫度的提高而降低且表現(xiàn)出明顯的再結(jié)晶特征。當(dāng)變形溫度在643~693 K時(shí)，激活能變化不大；當(dāng)溫度大于693 K時(shí)，激活能隨溫度升高而增大。當(dāng)溫度達(dá)到693 K時(shí)，合金發(fā)生了完全再結(jié)晶。Mg-9Y-3Zn-0.5Zr合金在693 K擠壓后的抗拉強(qiáng)度為340.0 MPa，伸長率為16.2%；該合金在時(shí)效后的抗拉強(qiáng)度為396.4 MPa，伸長率為6%, 時(shí)效抗拉強(qiáng)度明顯上升。
關(guān)鍵字: 鎂合金；Y；動(dòng)態(tài)再結(jié)晶；熱變形
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China; 2. School of Materials Science and Engineering, Beihang University, Beijing 100083, China; 3. School of Materials Science and Engineering, Huazhong University of Science and Technology,Wuhan 430074, China）
Abstract:The thermal deformation behavior of Mg-9Y-3Zn-0.5Zr magnesium alloy at the strain rates of 0.001−0.1 /s and in a temperature range from 543 K to 743 K performed on Gleeble−1500 hot simulator was studied. The results show that the true stress increases with increasing the stain rate at the same temperature, and decreases with increasing the temperature at the same strain rate with a characteristic of dynamic recrystallization. The deformation activation energy increases when the deformation temperature is over 693 K, and it is stable in the range of 643−693 K. The alloy exhibits a complete recrystallization at 693 K, the extruded alloy has a tensile strength of 340.0 MPa and an elongation of 16.2%, and after aging, the tensile strength is 396.4 MPa, the elongation is 6%.
Key words: magnesium alloy; Y; dynamic crystallization; hot deformation
