金属热处理 ›› 2020, Vol. 45 ›› Issue (1): 174-180.DOI: 10.13251/j.issn.0254-6051.2020.01.035

• 组织与性能 • 上一篇    下一篇

Al-4.5Cu-3.5Zn-0.5Mg铸造铝合金的均匀化工艺及组织演变

王南海, 易丹青, 王海生, 成勇   

  1. 中南大学 材料科学与工程学院, 湖南 长沙 410083
  • 收稿日期:2019-06-22 出版日期:2020-01-25 发布日期:2020-04-03
  • 通讯作者: 易丹青,教授,博士,主要从事轻合金和金属间化合物的制备、组织结构与性能研究,联系电话:13974870106,E-mail:Danqing@csu.edu.cn
  • 作者简介:王南海(1994—),男,硕士研究生,主要从事高强韧铸造铝合金研究,联系电话:17308416724,E-mail:wang_nanhai@126.com。

Homogenization process and microstructure evolution of Al-4.5Cu-3.5Zn-0.5Mg as-cast alloy

Wang Nanhai, Yi Danqing, Wang Haisheng, Cheng Yong   

  1. School of Materials Science and Engineering, Central South University, Changsha Hunan 410083, China
  • Received:2019-06-22 Online:2020-01-25 Published:2020-04-03

摘要: 对Al-4.5Cu-3.5Zn-0.5Mg铸态合金进行不同双级均匀化处理,采用扫描电镜、电子探针显微分析仪、差示扫描量热仪和光学显微镜等,研究了该合金的铸态组织及其在均匀化过程中的组织演变。结果表明:铸态组织主要由α-Al、粗大Al2Cu相以及少量AlZnMgCu、Al7Cu2Fe相组成,合金元素枝晶偏析严重。经470 ℃×12 h均匀化处理后,AlZnMgCu相已基本回溶至基体;第二级均匀化温度由490 ℃逐渐升高到520 ℃或者延长保温时间,Al2Cu相逐渐回溶至基体,合金元素分布趋于均匀。合金过烧温度为520 ℃,最佳双级均匀化制度为470 ℃×12 h+510 ℃×32 h,该制度与均匀化动力学计算结果基本一致。

关键词: Al-4.5Cu-3.5Zn-0.5Mg合金, 双级均匀化, 微观结构

Abstract: The microstructure of an as-cast Al-4.5Cu-3.5Zn-0.5Mg alloy and its evolution during different two-step homogenization treatments were studied by means of scanning electron microscope (SEM), electron probe micro-analyzer (EPMA), differential scanning calorimeter (DSC) and optical microscope (OM). The results show that the as-cast microstructure is mainly composed of α-Al and coarse Al 2 Cu phase with a small amount of AlZnMgCu and Al 7 Cu 2 Fe phases, and severe dendritic segregation of alloying elements exists in the alloy ingot. After homogenized at 470 ℃ for 12 h, the AlZnMgCu phase is mainly dissolved into the matrix. The Al 2 Cu phase is gradually dissolved into the matrix by increasing the second-step homogenization temperature from 490 ℃ to 520 ℃ or prolonging the holding time, and all the alloying elements tend to be homogenized. The over burnt temperature of the alloy is 520 ℃, and the proper homogenization process is 470 ℃×12 h+510 ℃×32 h, which agrees well with the kinetic calculation results of homogenization.

Key words: Al-4.5Cu-3.5Zn-0.5Mg alloy, two-step homogenization, microstructure

中图分类号: