Abstract: HPT was used to deform Al-Zn-Mg-Cu alloys under different deformation conditions. The effects of deformation parameters on microstructure and mechanics properties of the Al-Zn-Mg-Cu alloys were studied by scanning electron microscope（SEM）， energy dispersive spectrometer（EDS）， X-ray diffraction（XRD） and hardness examination. The results show that the initial microstructure is equiaxed with inhomogeneous distribution， the coarse second phase particles（Al2Cu、MgZn2）distribute along the grain boundaries. With the temperature and the number of twist turns increasing， the coarse second phase particles distributed in Al matrix reduce obviously and the distribution is more uniform. The second phase particles are re-dissolved in Al matrix and obtain a supersaturated solid solution. After HPT deformation， the dislocation density increases significantly. Otherwise the more the number of turns and deformation temperature， the larger the increase of dislocation density. On the contrary， the microcrystalline size decreases. The microhardness of Al-Zn-Mg-Cu alloy after HPT increases significantly with the temperature and the number of twist turns increasing.

Key words: Al-Zn-Mg-Cu alloy, high-pressure torsion（HPT）, microstructure, mechanics property

摘要： 以Al-Zn-Mg-Cu合金为研究对象，在不同变形工艺条件（扭转圈数、变形温度）下对其进行高压扭转试验，利用扫描电子显微镜（SEM）、能谱仪（EDS）、X射线衍射技术（XRD）以及硬度测试等手段分析变形工艺参数对合金微观组织和力学性能的影响规律。研究结果表明：原始铸态组织呈等轴状，分布不均匀，粗大的第二相粒子（Al2Cu、MgZn2）沿晶界呈链状分布；高压扭转变形过程中，随着变形温度的升高、扭转圈数的增多，基体组织中粗大的第二相粒子数量明显减少，分布更加均匀，第二相粒子回溶进Al基体，获得过饱和固溶体；高压扭转变形后的Al-Zn-Mg-Cu合金位错密度显著上升，并且扭转圈数越多，变形温度越高，位错密度增加幅度也越大，微晶尺寸则随着扭转圈数的增大和变形温度的升高而减小；高压扭转变形后Al-Zn-Mg-Cu合金显微硬度值总体上随扭转圈数增大和变形温度升高而增大。

关键词: Al-Zn-Mg-Cu合金, 高压扭转, 微观组织, 力学性能