The effect of artificial aging after multi-directional forging of supersaturated AA2024.

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.