中文摘要：

采用喷射沉积技术制备了Al-12Zn-2.4Mg-1.1Cu合金。通过高分辨电子显微镜和硬度测试等手段,研究分析了双级时效处理对喷射沉积Al-Zn-Mg-Cu合金微观组织和力学性能的影响。结果表明：合金经120℃（14 h）时效后,硬度达到峰值,晶内主要强化相为η′亚稳相和少量的GPⅡ区,晶界析出相呈连续分布;合金经120℃（14 h）＋160℃（0.5 h）、120℃（14 h）＋160℃（16 h）、120℃（14 h）＋160℃（24 h）双级时效后,硬度较峰时效相比,分别下降了5.92%、11.13%、15%,它们的晶内析出相依次是细小的η′相、粗大的η′相、粗大的η相,晶界析出相呈断续状分布,晶内和晶界的析出相明显长大,并且在120℃（14 h）＋160℃（16 h）、120℃（14 h）＋160℃（24 h）时效后,出现了晶界无沉淀析出带。通过对TEM图像的测量,可以得到η相和η′相的晶格参数分别为0.520、0.860 nm和0.490、1.402 nm;对η和η′相解卷处理,可以提高像的分辨率,然后用jems对η和η′相模拟,可以确定原子的基本位置。

英文摘要：

Al-12Zn-2.4Mg-1.1Cu alloy was prepared by the spray deposition method. The microstructure and mechanical properties of the spray-deposited alloy after two-step aging treatment were investigated by high-resolution electron microscopy and hardness tests. The results show that the η＇ phase and GP Ⅱ zones are major precipitates in the alloy after the ageing treatment at 120 ℃（14 h）. The hardness of the alloy increases to the top and the grain boundary precipitate phases are of continuous distribution. After the two-ageing treatment at 120 ℃（14 h）＋160 ℃（0.5 h）, 120 ℃（14 h）＋160 ℃（16 h） and 120 ℃（14 h）＋160 ℃（24 h）, the hardness of the alloy is reduced by 5.92%, 11.13% and 15%, respectively compared with those under peak-aged condition and the major precipitates are the fine η＇ phase, the coarse η＇ phase and the coarse η phase, respectively. The distributions of grain boundary precipitate phases are discontinuous. The grain boundary precipitate phases and the precipitate phases of grain interior have grown up obviously. After the two-ageing treatment at 120 ℃ （14 h）＋160 ℃ （16 h） and 120 ℃ （14 h）＋160 ℃ （24 h）, the precipitation free zones are also observed. Based on the measurement of TEM images, the lattice parameter of r/phase are 0.520 and 0.860 nm and those of η＇ phase are 0.490 and 1.402 nm. After the deconvolution processing on η and η＇ phase, the image resolution can be improved. Then, the η and η＇ phase were simulated by jems, and the basic position of atoms can be determined.