Influence of Stress‐Aging Processing on Precipitates and Mechanical Properties of a 7075 Aluminum Alloy |
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| Authors: | Y C Lin Yu‐Qiang Jiang Jin‐Long Zhang Xiao‐Min Chen |
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| Affiliation: | 1. School of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China;2. Light Alloy Research Institute of Central South University, Changsha 410083, China;3. State Key Laboratory of High Performance Complex Manufacturing, Changsha 410083, China |
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| Abstract: | Two‐step stress‐aging tests, as well as pre‐treatment plus stress‐aging experiments, are performed on a 7075 aluminum (Al–Zn–Mg–Cu) alloy. Influences of stress‐aging parameters on mechanical behavior and fracture mechanism are investigated through uniaxial tensile test and fracture morphology analysis. It is revealed that the stress‐aging dramatically influences the mechanical properties and fracture characteristics of the studied alloy, which is contributed to the sensitivity of microstructures to stress‐aging. When the alloy undergoes two‐step stress‐aging, the ultimate tensile strength and yield strength first increase and then decrease with the increased first step stress‐aging temperature, while the elongation first decreases and then increases. For the retrogression pre‐treated plus stress‐aged alloy, the yield strength first increases and then drops with the increased retrogression pre‐treatment time, while the ultimate tensile strength almost remains stable. Furthermore, the elongation continuously increases with the increased retrogression pre‐treatment time. The observation of fracture morphology indicates that the dimple‐type intergranular fracture is the main fracture mechanism for the two‐step stress‐aged and retrogression pre‐treated plus stress‐aged alloys. |
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| Keywords: | Alloy Stress‐aging Fracture mechanism Microstructural evolution Mechanical properties |
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