陈水生,段九一,徐志超,等.分级固溶处理对7075铝合金组织和综合性能的影响[J].河南理工大学学报(自然科学版)，doi:10.16186/j.cnki.1673-9787.2024060060.

CHEN S S, DUAN J Y, XU Z C, et al．Effect of multi-stage solution treatment on the microstructure and overall properties of 7075 aluminium alloy [J]. Journal of Henan Polytechnic University ( Natural Science)，doi:10.16186/j.cnki.1673-9787.2024060060.

分级固溶处理对7075铝合金组织和综合性能的影响 (网络首发)

陈水生¹，段九一¹，徐志超²，张楠楠¹，周洋¹

（1.河南理工大学 机械与动力工程学院, 河南 焦作 454000；2. 河南理工大学 材料科学与工程学院, 河南 焦作 454000）

摘要: 目的 室温成形性差是7075铝合金在轻量化车身结构中广泛应用的主要挑战，固溶工艺对7075铝合金的室温成形性能提升至关重要。为理解分级固溶工艺对7075铝合金在固溶态成形过程中的微观组织演变、力学性能和耐腐蚀性能的影响。 方法 通过微观组织分析、室温拉伸试验和电化学实验，对不同状态的7075铝合金的微观结构、力学性能及T6时效后的耐腐蚀性能进行分析。 结果 结果表明：（1）7075铝合金轧板第二相颗粒主要由η（MgZn2），S（Al2CuMg），CuAl2和Mg2Si构成。（2）经过475℃×4 h＋485℃×4 h＋495℃×2 h三级固溶工艺，固溶态7075铝合金组织中的η（MgZn2）相和S（Al2CuMg）相几乎完全溶解。（3）分级固溶工艺使合金中更多的溶质原子融入铝基体中，合金的组织成分更加均匀，再结晶程度增大，较单级固溶工艺，固溶态合金的抗拉强度和断裂伸长率分别增加了11.9%和22.2%。（4）T6时效后，7075铝合金发生再结晶软化和析出强化，较单级固溶工艺，三级固溶工艺处理的合金抗拉强度和硬度分别下降了2.5%和0.8%。（5）随着S（Al2CuMg）相颗粒的溶解，时效后合金的电荷传递性能下降，自腐蚀电流密度减小，可有效提升时效后合金的耐腐蚀性能。 结论 合理的三级固溶工艺，可有效提高固溶态7075铝合金第二相颗粒的溶解度，在保障时效后力学性能前提下，大幅度提升固溶态7075铝合金室温成形性能和T6态合金的耐腐蚀性能。

关键词: 固溶态；组织演变；室温成形；力学性能；耐腐蚀性能

doi:10.16186/j.cnki.1673-9787.2024060060

基金项目: 国家自然科学基金资助项目（52103290）；河南省高等学校重点科研项目(24A460013)

收稿日期：2024-06-29

修回日期：2024-11-02

网络首发日期：2025-10-27

Effect of multi-stage solution treatment on the microstructure and overall properties of 7075 aluminium alloy

CHEN Shuisheng¹, DUAN Jiuyi¹, XU Zhichao², ZHANG Nannan¹, ZHOU Yang¹

(1. School of Mechanical and Power Engineering, Henan Polytechnic University, Jiaozuo 454000, Henan, China; 2. School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, Henan, China)

Abstract: Objectives Poor room-temperature formability is the main challenge for 7075 aluminium alloy in its wide application in lightweight body structures, the solid solution process is vital to enhance the room temperature forming properties of 7075 aluminium alloy. To understand the effects of multi-stage solid solution process on the microstructure, mechanical properties and corrosion resistance of 7075 aluminium alloy during solid solution forming. Methods The microstructure analysis, tensile testing, and electrochemical experiment were employed to investigate the microstructure and mechanical properties of 7075 aluminum alloy in different states, as well as the corrosion resistance properties after T6 aging. Results The results show that: (1) the second phase particles of 7075 aluminum alloy rolled sheet are mainly composed of η (MgZn2), S (Al2CuMg), CuAl2 and Mg2Si. (2) After 475 ℃×4 h + 485 ℃×4 h + 495 ℃×2 h of three-stage solid solution process, η (MgZn2) and S (Al2CuMg) phase in the solid solution state of 7075 aluminum alloy is nearly completely dissolved.(3) The multi-stage solid solution process makes more solute atoms in the alloy to be dissolved into the aluminium matrix, resulting in more homogeneous composition and more recrystallization, and after which the tensile strength and elongation at break of the alloy in the solid solution state increase by 11.9% and 22.2% respectively compared to those after the single-stage solid solution process. (4) After T6 aging, recrystallization softening and precipitation strengthening occur, the tensile strength and hardness of the alloy treated by three-stage solid solution process decreased by 2.5% and 0.8%, respectively, comparing with those of the single-stage solid solution process. (5) With the dissolution of S(Al2CuMg) particles, the charge transfer property of the aged alloy and the self-corrosion current density decreases, which can effectively improve the corrosion resistance of the aged alloy. Conclusions Proper three-stage solid solution process can effectively improve the solubility of the second phase particles of solid solution 7075 aluminium alloy, which significantly improves the room temperature forming performance of 7075 aluminium alloy and the corrosion resistance of the alloy in T6 state under the premise of ensuring the mechanical properties of the alloy after aging.

Key words: solid solution state; microstructure evolution; room temperature forming; mechanical properties; corrosion resistance