Abstract

Particle dissolution and recrystallization progress of Al–Mg–Si–Cu alloy during solution treatment at 555°C was studied by microstructure, hardness and electrical conductivity characterization, and analytical calculation in the present study. The results show that recrystallization and dissolution could occur concurrently during solution treatment, and the solution time has an appreciable influence on hardness, electrical conductivity, secondary phase particles and grain structure of the Al–Mg–Si–Cu alloy. As the solution time increases, the hardness decreases at first, and then increases, and almost remains constant finally; the electrical conductivity decreases sharply at first, and then decreases slowly, and almost keeps constant finally. In addition, the microstructure transforms from the deformation elongated bands to recrystallization equiaxed grains, and the particles are gradually dissolved with the increase of the solution time. The dissolution of the particles may be completed in the range of 120–300 s and the recrystallization was finished not exceeding 60 s. The predicted dissolution time by an analytical model combining classical diffusion-controlled dissolution equation for a single spherical particle and a John–Mehl–Avarami-like (JMA-like) equation is approximately 170 s, which is consistent with the experimental results.

中文翻译：

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Al-Mg-Si-Cu合金固溶处理过程中的颗粒溶解与再结晶过程

摘要

通过显微组织，硬度和电导率表征以及本研究的分析计算，研究了Al-Mg-Si-Cu合金在555°C固溶处理过程中的颗粒溶解和重结晶过程。结果表明，固溶处理可能同时发生再结晶和溶解，固溶时间对Al-Mg-Si-Cu合金的硬度，电导率，第二相颗粒和晶粒结构有显着影响。随着固溶时间的增加，硬度先降低，然后增加，最后几乎保持不变；首先，电导率急剧下降，然后缓慢下降，最后几乎保持恒定。此外，微观组织从变形拉长带转变为重结晶等轴晶，随着固溶时间的增加，颗粒逐渐溶解。颗粒的溶解可能在120-300 s的范围内完成，重结晶完成不超过60 s。通过分析模型将单个球状颗粒的经典扩散控制溶出方程与John-Mehl-Avarami-like（JMA-like）方程相结合的预测模型的预计溶出时间约为170 s，这与实验结果相符。