Woźnicki Antoni, Leszczyńska-Madej Beata, Włoch Grzegorz, Madura Jacek, Bogusz Marek, Leśniak Dariusz
Aptiv Services Poland S.A., 30-399 Kraków, Poland.
Faculty of Non-Ferrous Metals, AGH University of Science and Technology, 30-059 Kraków, Poland.
Materials (Basel). 2023 Mar 3;16(5):2091. doi: 10.3390/ma16052091.
Within the present work the homogenization of DC-cast (direct chill-cast) extrusion billets of Al-Mg-Si-Cu alloy was investigated. The alloy is characterized by higher Cu content than currently applied in 6xxx series. The aim of the work was analysis of billets homogenization conditions enabling maximum dissolution of soluble phases during heating and soaking as well as their re-precipitation during cooling in form of particles capable for rapid dissolution during subsequent processes. The material was subjected to laboratory homogenization and the microstructural effects were assessed on the basis of DSC (differential scanning calorimetry) tests, SEM/EDS (scanning electron microscopy/energy-dispersive spectroscopy) investigations and XRD (X-ray diffraction) analyses. The proposed homogenization scheme with three soaking stages enabled full dissolution of Q-AlCuMgSi and θ-AlCu phases. The β-MgSi phase was not dissolved completely during soaking, but its amount was significantly reduced. Fast cooling from homogenization was needed to refine β-MgSi phase particles, but despite this in the microstructure coarse Q-AlCuMgSi phase particles were found. Thus, rapid billets heating may lead to incipient melting at the temperature of about 545 °C and the careful selection of billets preheating and extrusion conditions was found necessary.
在本研究中，对Al-Mg-Si-Cu合金的DC铸造（直接水冷铸造）挤压坯料的均匀化进行了研究。该合金的特点是铜含量高于目前应用于6xxx系列合金中的铜含量。本研究的目的是分析坯料的均匀化条件，以便在加热和保温过程中使可溶相最大程度地溶解，并在冷却过程中使其以能够在后续加工过程中快速溶解的颗粒形式重新析出。对该材料进行了实验室均匀化处理，并基于差示扫描量热法（DSC）测试、扫描电子显微镜/能谱仪（SEM/EDS）研究和X射线衍射（XRD）分析评估了微观结构效应。所提出的具有三个保温阶段的均匀化方案能够使Q-AlCuMgSi相和θ-AlCu相完全溶解。β-MgSi相在保温过程中未完全溶解，但其含量显著降低。需要从均匀化温度快速冷却以细化β-MgSi相颗粒，但尽管如此，在微观结构中仍发现了粗大的Q-AlCuMgSi相颗粒。因此，坯料快速加热可能会在约545°C的温度下导致初期熔化，并且发现必须谨慎选择坯料的预热和挤压条件。
