(1. 中南大学 材料科学与工程学院 有色金属材料科学与工程教育部重点实验室，长沙 410083；2. 长沙大学 机电工程系，长沙 410003)
摘 要: 采用光学显微镜、扫描电镜和透射电镜等研究7B50高强铝合金铸态和均匀化态的显微组织与成分分布，确定了实验合金一级均匀化后的过烧温度及二级均匀化工艺。结果表明：实验合金经465 ℃，24 h均匀化后的过烧温度为480 ℃，其最佳二级均匀化退火工艺为随炉升温到465 ℃保温24 h，再随炉升温到475 ℃保温4 h；实验合金经二级均匀化处理后，成分均匀，残留共晶很少，基体上析出大小适中及分布均匀的Al3Zr质点。
关键字: 7B50铝合金；均匀化；显微组织
（1. School of Materials Science and Engineering, Key Laboratory of Non-Ferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083, China;2. Department of Mechanical and Electrical Engineering, Changsha University, Changsha 410003, China）
Abstract:The microstructure and the composition distribution of as-cast and homogenized aluminium alloy 7B50 were studied by means of optical micrography, scanning electron micrography and transmission electron micrography. The overheating temperature of the alloy homogenized at 465 ℃ for 24 h and the two-step homogenization parameters were determined. The results indicate that the overheating temperature of the alloy homogenized at 465 ℃ for 24 h is 480 ℃, and the two-step homogenizing process is optimized. After the studied alloy is treated with the two-step homogenizing process, the alloy elements are uniformly distributed, the pseudoeutectic is little and the Al3Zr particles are uniformly precipitated in the matrix.
Key words: 7B50 aluminum alloy; homogenization; microstructure
