(1. 中南大学 材料科学与工程学院，长沙 410083；
2. 中国商用飞机有限责任公司 上海飞机设计研究院，上海 200232)
摘 要: 采用差热分析、X射线衍射分析、光学显微镜、扫描电镜、透射电镜和常温拉伸等方法研究分级均匀化工艺对7055铝合金显微组织、枝晶偏析、Al3Zr粒子析出行为和力学性能的影响。结果表明：合金经(468 ℃、24 h)+(473 ℃、4 h)的分级均匀化处理后，消除了铸锭晶界上的非平衡凝固共晶组织；铸锭先于264 ℃保温最有利于获得尺寸细小、均匀弥散分布的Al3Zr粒子；在单级均匀化基础上增加473 ℃的短时高温均匀化，能够提高合金基体中溶质原子的固溶度，增强时效强化效果，提高综合性能。
关键字: 7055铝合金；均匀化；Al3Zr粒子；显微组织；力学性能
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Shanghai Aircraft Design and Research Institute, Commercial Aircraft Corporation of China, Shanghai 200232, China）
Abstract:The effects of step-homogenization on the microstructures, dendritic segregation, precipitation of Al3Zr particles and ultimate mechanical properties of aluminum alloy 7055 were studied by differential scanning calorimetry, X-ray diffractometry, optical microscopy, scanning electron microscopy, transmission electron microscopy and tensile test. The result show that the step-homogenization treatment, which comprises of the isothermal heating of the ingots at 468 ℃ for 24 h, then heating to 473 ℃ for 4 h, greatly eliminates the nonequilibrium solidified eutectic which exists on the grain boundaries. The previous heating at 264 ℃ is most favorable for the precipitation of fine and uniformly distributed Al3Zr particles. The additional short-term and high temperature heating at 473 ℃ on the basis of single-stage homogenization maximizes the solution ability of solid solute in the matrix, enhances the ageing strengthening effect and improves the comprehensive properties of the alloy.
Key words: 7055 aluminum alloy; homogenization; Al3Zr particles; microstructure; mechanical properties
