分级均匀化对7055铝合金组织和力学性能的影响  

Effect of step-homogenization on microstructures and mechanical properties of 7055 aluminum alloy

作　　者：张新明[1] 陆艳红[1] 刘胜胆[1] 刘文军[1] 李红萍[2] 

机构地区：[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

出　　处：《中国有色金属学报》2012年第8期2154-2162,共9页The Chinese Journal of Nonferrous Metals

基　　金：国家重点基础研究发展计划资助项目(2005CB623706)

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℃、24h)+(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。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.

关 键 词：7055铝合金 均匀化 Al3Zr粒子 显微组织 力学性能 

分 类 号：TG146.1[一般工业技术—材料科学与工程]