(1. 中南大学 材料科学与工程学院，长沙 410083；
2. 中南大学 有色金属材料科学与工程教育部重点实验室，长沙 410083)
摘 要: 通过透射电镜观察和XRD检测分析，对比纯Al试样，研究了多向压缩变形(MAC)过程中固溶原子及析出相对Al-4Cu合金晶粒细化效果的影响。结果表明：室温下，经过相同变形道次后，固溶原子的存在导致Al-4Cu合金所形成的亚晶粒形貌不规则，晶内位错密度较高，呈长约200 nm、宽约100 nm的类竹节状，纯Al中亚晶粒内部位错密度低，呈直径约600 nm的等轴状；Al-4Cu合金在室温下的析出相回溶过程抑制细小晶粒的形成，有利于亚晶内部位错密度的降低，50 ℃下的析出相回溶及再析出过程有利于细小晶粒的形成。
关键字: Al-4Cu合金；强变形；析出相回溶；晶粒尺寸；亚晶
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education,
Central South University, Changsha 410083, China）
Abstract:The size and morphology of pure Al and Al-4Cu alloy processed by multi-axial compression (MAC) deformation were characterized by transmission electron microscopy and X-ray diffractometry to investigate the effect of solute atom and precipitated phase on grain refinement of Al-4Cu alloy by severe plastic deformation. The results show that the existence of solute atom in Al-4Cu alloy is associated with the irregular morphology of subgrain and higher dislocation density than that of pure Al. However, the former in bamboo-like shape exhibits smaller grain size with a length of about 200 nm and a width of about 100 nm than the latter in equiaxed shape with a diameter of about 600 nm. Also, at room temperature grain refinement is suppressed by the re-dissolution of severely deformed precipitated phase, which is helpful to the decrease of dislocation density, and at 50 ℃ the re-dissolution and re-precipitation of precipitate phase contributes to the grain refinement.
Key words: Al-4Cu alloy; severe plastic deformation; precipitated phase re-dissolution; grain size; subgrain
