Rashidi Mohadeseh, Abdian Mohammad, Kazeminezhad Mohsen
Department of Materials Science and Engineering, Sharif University of Technology, Azadi Avenue, Tehran, Iran.
Sci Rep. 2025 Jul 15;15(1):25467. doi: 10.1038/s41598-025-11453-5.
The primary objective of this study is to determine the most effective solution treatment and aging temperature for AA2024 aluminum alloy to achieve superior mechanical properties. In this research, a Severe Plastic Deformation (SPD) method known as Multi-Directional Forging (MDF), which is one of the useful methods for creating Ultra-Fine Grained (UFG) microstructure, was employed on AA2024. Due to the limited studies on the effects of artificial aging on this alloy in its supersaturated state following the MDF process, the alloy was subjected to solution treatments at 480 °C, 500 °C, and 520 °C for 1 h, followed by immediate MDF. Aging was then performed at 100 °C, 140 °C, 190 °C, 240 °C, and 290 °C for 1 h each, to achieve artificial aging. To investigate the microstructure and precipitate conditions, Optical Microscopy (OM) and Field Emission Scanning Electron Microscopy (FE-SEM) were used to analyze the cross-sectional surfaces of the samples. Mechanical properties were evaluated through hardness and compression tests. The study reveals that the sample solution-treated at 520 °C exhibited the highest hardness and yield stress compared to those treated at 480 °C and 500 °C. The hardness of MDF samples increased from 82 HV to 165 HV as the aging temperature rose to 140 °C, where the highest hardness, flow stress, and yield strength were observed. At 190 °C for aging temperature, full recrystallization occurred, and at 240 °C and 290 °C, grain growth was observed, leading to a decrease in hardness, 128 HV and 97 HV, and yield strength, 505 MPa and 386 MPa, respectively. The results demonstrate that a solution treatment at 520 °C followed by artificial aging at 140 °C produces the best mechanical properties and microstructural characteristics in the AA2024 alloy, achieving the flow stress of 791 MPa and yield stress of 621 MPa.
本研究的主要目的是确定用于AA2024铝合金的最有效的固溶处理和时效温度，以获得优异的力学性能。在本研究中，对AA2024采用了一种称为多向锻造（MDF）的严重塑性变形（SPD）方法，这是一种用于创建超细晶粒（UFG）微观结构的有效方法。由于关于人工时效对经过MDF处理的该合金过饱和状态影响的研究有限，该合金在480℃、500℃和520℃下进行1小时的固溶处理，随后立即进行MDF处理。然后分别在100℃、140℃、190℃、240℃和290℃下进行1小时的时效处理，以实现人工时效。为了研究微观结构和析出条件，使用光学显微镜（OM）和场发射扫描电子显微镜（FE-SEM）分析样品的横截面。通过硬度和压缩试验评估力学性能。研究表明，与在480℃和500℃处理的样品相比，在520℃进行固溶处理的样品表现出最高的硬度和屈服应力。随着时效温度升至140℃，MDF样品的硬度从82 HV增加到165 HV，此时观察到最高的硬度、流变应力和屈服强度。在时效温度为190℃时，发生了完全再结晶，在240℃和290℃时，观察到晶粒长大，导致硬度分别降至128 HV和97 HV，屈服强度分别降至505 MPa和386 MPa。结果表明，在520℃进行固溶处理，然后在140℃进行人工时效，可使AA2024合金获得最佳的力学性能和微观结构特征，实现791 MPa的流变应力和621 MPa的屈服应力。
