(1. 重慶大學(xué) 材料科學(xué)與工程學(xué)院，重慶 400044；
2. 國家鎂合金材料工程技術(shù)研究中心，重慶 400045)
摘 要: 采用Gleeble-1500熱/力模擬試驗機進行壓縮實驗，研究Mg-2Zn-1Mn (ZM21)與Mg-6Zn-1Mn (ZM61)合金在變形溫度523~723 K、應(yīng)變速率0.01~10 s-1范圍內(nèi)的流變應(yīng)力行為，并以熱壓縮實驗為基礎(chǔ)，建立兩種合金的動態(tài)模型加工圖，引入材料加工硬化率θ，結(jié)合θ—σ曲線拐點判據(jù)識別合金發(fā)生動態(tài)再結(jié)晶的臨界應(yīng)變εc。結(jié)果表明，ZM21與ZM61合金在熱壓縮過程中發(fā)生明顯的動態(tài)回復(fù)與動態(tài)再結(jié)晶；隨著Zn含量的增加，ZM61合金的變形激活能比ZM21合金的升高約20%，并且ZM61合金在高溫變形時更容易出現(xiàn)失衡；兩者發(fā)生動態(tài)再結(jié)晶的臨界應(yīng)變εc均隨著應(yīng)變速率的增加而升高，隨變形溫度的升高而降低。
關(guān)鍵字: 鎂合金；熱壓縮；動態(tài)再結(jié)晶；臨界應(yīng)變
（1. College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China;
2. National Engineering Research Center for Magnesium Alloys, Chongqing 400045, China）
Abstract:The thermal compression behavior of Mg-2Zn-1Mn (ZM21) and Mg-6Zn-1Mn (ZM61) magnesium alloys was investigated by uniaxial compression tests on Gleeble-1500 thermal simulation test machine at the temperature ranging from 523 K to 723 K and strain rate ranging from 0.01 s-1 to 10 s-1. According to the experimental results, the hot processing maps based on the dynamic materials modeling were drawn. The critical strain εc that the dynamical recrystallization occurs was identified by introducing the hard working rate θ and inflection point of θ—σ curves under different deformation. The results show that the dynamic recovery and dynamic recrystallization occur obviously during hot compression of ZM21and ZM61 alloys. Compared with ZM21 alloy, the deformation activation energy of ZM61 alloy increases by 20% because of the increase of Zn content, and the ZM61 alloy is more unstable than ZM21 alloy. The critical strain εc of both alloys increases with the increase of strain rate and decreases with the increase of deformation temperature.
Key words: magnesium alloy; thermal compression; dynamic recrystallization; critical strain
