(1. 湖南科技大学 难加工材料高效精密加工湖南省重点实验室，湘潭 411201；
2. 中南大学 高等研究中心，长沙 410083；
3. 湖南科技大学 高温耐磨材料及制备技术湖南省国防技术重点实验室，湘潭 411201)
摘 要: 制备不含粗大S相(1号合金)和富含粗大S相(2号合金)两种典型组织特征的2E12合金。结合热模拟实验和显微组织观察，针对两种合金在340~490 ℃、0.001~10 s-1下的变形行为开展研究。结果表明：除(490 ℃，0.001 s-1)的变形条件下，2号合金在相同变形条件下比1号合金拥有更高的峰值应力。在(340 ℃，10 s-1)变形条件下，1号合金和2号合金的主要失效形式分别为三叉晶界的变形失稳和S相脆裂引起的沿晶开裂。在(490 ℃，0.001 s-1)的变形条件下，晶界处S相完全弱化导致2号合金出现明显的晶界开裂。在变形过程中，合金晶内的T相和S相均对位错运动具有较强的阻碍作用，能强化合金并且促进合金的均匀变形。在回复阶段，晶内的T相和S相能钉扎亚晶界从而起到细化晶粒的作用。
关键字: 2E12铝合金；热变形；S相
（1. Hunan Provincial Key Laboratory of High Efficiency and Precision Machining of Difficult-to-cut Material,
Hunan University of Science and Technology, Xiangtan 411201, China;
2. Advanced Research Center, Central South University, Changsha 410083, China;
3. Key Laboratory of High Temperature Wear Resistant Materials Preparation Technology of
Hunan Province, Xiangtan 411201, China）
Abstract:Two kinds of alloys featured with free of S phase (alloy 1) and enriched with S phase (alloy 2) were prepared. Combined isothermal hot compression test and microstructure observation, the hot deformation behaviors of two alloys were studied at the temperature range of 340-490 ℃ and strain rate range of 0.001-10 s-1. The results show that, compared with alloy 1, alloy 2 possesses higher peak-stress when deformed at the same conditions. When deformed at (340 ℃, 10 s-1), the main failure modes for alloy 1 and alloy 2 are unstable deformation at triple grain boundaries (GBs) and intergranular cracking caused by brittle fracture of S phase, respectively. When deformed at (490 ℃, 0.001 s-1), the S phase located at GB is completely weakened which leads to the intergranular cracking of alloy 2. During deformation, the grain interior S phase and T phase not only hinder dislocation motion but also promote homogenous deformation of alloy. During recovery, the grain interior S phase and T phase can pin subgrain boundaries and thus refine grain size.
Key words: 2E12 aluminium alloy; hot deformation; S phase
