(1. 东北大学 轧制技术及连轧自动化国家重点实验室，沈阳 1108192；
2. 燕山大学 国家冷轧板带装备及工艺工程技术研究中心，秦皇岛 066004；
3. 广西先进铝加工创新中心有限责任公司，南宁 530007)
摘 要: 采用真空离心铸造工艺制备了7055铝合金铸管坯，通过金相观察(OM)、扫描电镜(SEM)、电子探针(EPMA)分析以及硬度测试研究了铸管坯的微观组织与力学性能。结果表明：铸管坯组织呈梯度分布，从管坯的外层到内层金属间化合物面积比例、平均尺寸以及晶粒尺寸逐渐增加，晶粒形状由外层的细小等轴晶逐渐过度到内层的粗大枝晶，溶质元素浓度以及硬度逐渐增加；经均匀化热处理后，从管坯外层到内层析出相T相含量逐渐增加，合金外层和中层的硬度略有降低，而内层硬度大幅下降。为保证组织均匀性和性能的稳定性，该管坯厚度以不超过12 mm为宜。
关键字: 7055铝合金；T相；真空离心铸造；微观组织；硬度
（1. State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, China;
2. National Engineering Research Center for Equipment and Technology of Cold Strip Rolling, Yanshan University, Qinhuangdao 066004, China;
3. Guangxi Advanced Aluminum Processing Innovation Center Co., Ltd., Nanning 530007, China）
Abstract:The 7055 aluminum alloy casting tube was prepared by vacuumed centrifugal casting process, and the microstructure and mechanical properties of the tube were studied by metallographic observation (OM), scanning electron microscope (SEM), electron probe microanalysis (EPMA) and hardness test. The results show that the as-cast microstructure presents gradient distribution. From the outer layer to the inner layer, the area fraction, average size and grain size of intermetallic compounds gradually increase, the grains gradually transit from equiaxed grains in the outer layer to dendrites in the inner layer, and the element content and hardness also gradually increase. After homogenization heat treatment, the precipitated phase (T phase) increases gradually from the outer layer to the inner layer of the tube, while the hardness of the outer layer and the middle layer of the alloy decreases slightly, while the hardness of the inner layer decreases greatly. In order to ensure the uniformity of microstructure and stable performance, the thickness of the tube should not exceed 12 mm.
Key words: 7055 aluminum alloy; T phase; vacuumed centrifugal casting; microstructure; mechanical properties
