(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院， 長沙410083；
2. 中南大學(xué) 有色金屬材料科學(xué)與工程教育部重點(diǎn)實(shí)驗(yàn)室， 長沙410083)
摘 要: 采用熱模擬實(shí)驗(yàn)對Al-Cu-Mg-Ag耐熱鋁合金進(jìn)行熱壓縮實(shí)驗(yàn)，研究合金在熱壓縮變形中的流變應(yīng)力行為和變形組織。結(jié)果表明：Al-Cu-Mg-Ag耐熱鋁合金在熱壓縮變形中的流變應(yīng)力隨著溫度的升高而減小，隨著應(yīng)變速率的增大而增大；該合金的熱壓縮變形流變應(yīng)力行為可用雙曲正弦形式的本構(gòu)方程來描述，其變形激活能為196.27 kJ/mol；在變形溫度較高或應(yīng)變速率較低的合金中發(fā)生部分再結(jié)晶，并且在合金組織中存在大量的位錯(cuò)和亞晶；隨著溫度的升高和應(yīng)變速率的降低，合金中拉長的晶粒發(fā)生粗化，亞晶尺寸增大，位錯(cuò)密度減小，合金的主要軟化機(jī)制逐步由動(dòng)態(tài)回復(fù)轉(zhuǎn)變?yōu)閯?dòng)態(tài)再結(jié)晶。
關(guān)鍵字: Al-Cu-Mg-Ag合金；耐熱鋁合金；熱壓縮變形；流變應(yīng)力
Al-Cu-Mg-Ag alloy during hot compression deformation
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. The Key Laboratory of Nonferrous Materials Science and Engineering of Ministry of Education, Central South University, Changsha 410083, China）
Abstract: The behavior of the flow stress and the deformation microstructure of heat-resistant aluminum alloy Al-Cu-Mg-Ag during hot compression deformation were studied by thermal simulation test. The results show that the flow stress decreases with increasing deforming temperature and increases with increasing strain rate. The flow stress of the alloy during hot compression deformation can be described by constitutive equation in hyperbolic sine function with a hot deformation activation energy of 196.27 kJ/mol. Partial recystallization takes place in the alloys deformed at a high temperature or at a low strain rate, and large number of dislocations and subgrains are observed in the alloy. The elongated grains observed in the samples coarsen with increasing temperature and decreasing strain rate. Correspondingly, the subgrain size increases and the dislocation density decreases. The main soften mechanism of the alloy transforms from dynamic recovery to dynamic recrystallization.
Key words: Al-Cu-Mg-Ag alloy; heat-resistant aluminum alloy; hot compression deformation; flow stress
