Al-Zn-Mg-Cu-Li合金均匀化与固溶热处理工艺优化

                                     Al-Zn-Mg-Cu-Li合金均匀化与固溶热处理工艺优化

许军军，袁  欣，明文全^*，伍翠兰，陈江华^*

（1.湖南大学材料科学与工程学院，湖南长沙，410082；2.海南大学材料科学与工程学院，海南海口，570228）

摘  要  本文研究了Al-7.4Zn-1.5Mg-1.7Cu-1.1Li（wt.%）合金在不同均匀化和固溶处理条件下的显微组织和力学性能。结果表明，该铝合金的铸态组织主要由α-Al基体、Li₃CuAl₅相和Mg₃₂(Al, Zn)₄₉相构成。为充分溶解第二相，提高过饱和固溶度，需要改善该含Li合金的热处理工艺。优化后的热处理工艺为510 ℃/24 h均匀化处理加510 ℃/1 h固溶处理。对比发现，使用优化后的热处理工艺可明显减少该合金中第二相颗粒的含量，且不发生过烧。相比传统均匀化和固溶热处理制度（460 ℃/24 h+475 ℃/1 h），采用新的均匀化和固溶工艺后，合金120 ℃时效峰值硬度提升了34.3 HV，提升幅度约22%。

关键词  Al-Zn-Mg-Cu；Li；均匀化处理；固溶处理；显微组织

中图分类号：TG146.2；TG115.21+5.3  文献标识码：A  doi:10.3969/j.issn.1000-6281.2023.05.004

                               Optimization of homogenization and solution heat treatmentprocess in Al-Zn-Mg-Cu-Li Alloy

XU Jun-jun¹，YUAN Xin¹，MING Wen-quan^2*，WU Cui-lan¹，CHEN Jiang-hua^1，2*

(1. College of Materials Science and Engineering, Hunan University, Changsha Hunan 410082, China; 2. School of Materials Science and Engineering, Hainan University, Haikou Hainan 570228, China)

Abstract   The microstructure and mechanical properties of Al-7.4Zn-1.5Mg-1.7Cu-1.1Li (wt.%) alloys under different conditions of homogenization and solution treatment were studied. The results show that the as-cast microstructure of aluminum alloy is mainly composed of α-Al matrix, Li₃CuAl₅ phase and Mg₃₂(Al, Zn)₄₉ phase. The optimized heat treatment process is 510 ℃/24 h homogenization treatment plus 510 ℃/1 h solution treatment. The optimized heat treatment process can significantly reduce the content of the second phase particles in the alloy without burning. Compared with the traditional homogenization and solution heat treatment (460 ℃/24 h+475 ℃/1 h), the peak hardness of the alloy aged at 120 ℃ is increased by 34.3 HV with an increasing rate of about 22 % after adopting the new homogenization and solution process.

Keywords Al-Zn-Mg-Cu；Li；homogenization；solution treatment；microstructure

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