Mechanical and Corrosion Properties of AA2024 Aluminum Alloy with Multimodal Gradient Structures

Enhancing the strength and toughness of aluminum alloys using microstructure optimization remains a key challenge. In this study, an AA2024 aluminum alloy with a double-layer multi-gradient structure was fabricated using 50% constrained deformation and single-stage peak aging at 150 °C. Microstructu...

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Bibliographic Details
Main Authors: Zhenwei Xie, Liexing Zhou, Jun Li, Yonghua Duan, Mingjun Peng, Hongbo Xiao, Xiong Du, Yuanjie Zhao, Mengnie Li
Format: Article
Language:English
Published: MDPI AG 2025-02-01
Series:Metals
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Online Access:https://www.mdpi.com/2075-4701/15/2/177
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Summary:Enhancing the strength and toughness of aluminum alloys using microstructure optimization remains a key challenge. In this study, an AA2024 aluminum alloy with a double-layer multi-gradient structure was fabricated using 50% constrained deformation and single-stage peak aging at 150 °C. Microstructural and compositional analysis was performed using SEM, XRD, and TEM to investigate grain structures, dislocation density, and the distribution of precipitated phases. The results revealed a heterogeneous microstructure with variations in grain size, dislocation gradient, and precipitation phases between the constrained and deformation layers. Mechanical testing demonstrated a 30.9% increase in yield strength, a 16.4% increase in tensile strength, and a 13.9% improvement in uniform elongation compared to the T6 temper. Corrosion tests showed enhanced resistance, with a shallower intergranular corrosion depth and higher self-corrosion potential. The improved mechanical properties were attributed to the dislocation gradient and heterogeneous precipitation phases, while the enhanced corrosion resistance resulted from the transformation of the S phase from a continuous grain boundary distribution to a discontinuous distribution along dislocations. This study provides a novel approach for optimizing the mechanical and corrosion properties of AA2024 aluminum alloy using microstructure design and precise thermal–mechanical treatment.
ISSN:2075-4701