摘要
采用光学显微镜(OM),扫描电镜(SEM)结合能谱分析(EDS)研究了主要合金元素对7000系铝合金铸态和均匀化状态组织的影响。结果表明:铸态条件下,含Cu合金存在明显的Cu元素晶界偏析,而不含Cu合金没有明显的偏析现象。对含Cu合金且Zn/Mg>1.5时,合金中的第二相粒子在晶界或者枝晶界上呈断续分布,主要是η(MgZn2)相;Zn/Mg<1.5时,合金中的第二相粒子在晶界或枝晶界上呈连续分布,主要是S(Al2CuMg)相。经过均匀化工艺处理后,前者易溶解,后者难以溶解。无Cu合金中的粗大第二相粒子主要是Al5Mg11Zn4相,均匀化处理易溶。除此之外,均匀化后的合金中总会含有少量的杂质相Al3Fe相或Al7Cu2Fe相。经过系统的分析,绘制了第二相粒子与合金成分之间的关系图。
The effects of the main alloy elements on the microstructures of as-cast and homogenization treated state of 7000 series aluminum alloys were investigated using optical microscopy （ OM ）, scanning electron microscopy （ SEM ） combined with energy dispersive spectrometry （EDS）. The results show that severe dendritic segregation exists in as-cast alloys including Cu, while dendritic segregation is not found in as-cast alloys without Cu. In alloys with Cu and Zn/Mg 〉 i. 5, η phase （ MgZn2 ） is the main second phase, and η particles are discontinuously distributed at the grain boundaries or interdendritic boundaries. They dissolve back to the matrix during homogenization treatment. However, if Zn/Mg 〈 1.5, S phase （A12 CuMg） is the main second phase, and S particles are continuously distributed at the grain boundaries or interdendritic boundaries. They hardly dissolve back to the matrix during homogenization treatment. As for alloys of Cu free, the main constituent is Al5 Mg. Zn4. Besides these second phases, there are always a small amount of impurity phases such as A13 Fe or A17Cu2Fe remained in alloys after homogenization. Through systematic analysis, a diagram illustrating the relationship between alloy composition and second phases was given out.
出处
《电子显微学报》
CAS
CSCD
2013年第1期6-13,共8页
Journal of Chinese Electron Microscopy Society
基金
国家重点基础研究发展计划资助项目(No.2009CB623704)
国家自然科学基金资助项目(No.50771043)
湖南省高校科技创新团队项目
关键词
铝合金
铸态组织
均匀化
第二相
aluminum alloys
as-cast microstructure
homogenization
second phase
