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.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
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)
