微量Zr对Al-Cu-Mg合金时效硬化行为及显微结构的影响
蒋 成，任抒琪，刘翠秀*，孙 威*微量Zr对Al-Cu-Mg合金时效硬化行为及显微结构的影响
蒋 成，任抒琪，刘翠秀*，孙 威*
（北京工业大学材料与制造学部固体微结构与性能研究所，北京100124）
摘 要 本文应用维氏硬度仪和透射电镜研究了微量Zr添加对Al-Cu-Mg合金180℃时效硬化行为及对应析出结构的影响。结果表明，Zr元素的添加对时效初期合金的硬度提升影响不大，但对峰值及过时效阶段合金的硬度有明显的增强作用。具有较高空位结合能的Zr容易与合金的空位结合，限制了时效初期合金中其它溶质原子的析出速率。而随着时效时间的延长，Zr元素的存在趋向促进细小的S及θ′相的弥散析出，提高合金的峰值硬度；同时Zr添加能够有效地抑制θ′相的过度粗化，并在过时效阶段使Al-Cu-Mg合金基体中的θ′相保持较高的径厚比，可有效提高过时效合金的硬度及热稳定性。
关键词 Al-Cu-Mg合金；Zr添加；时效处理；微观结构；电子显微表征
中图分类号：TG146.2；TG115.21+5.3
文献标识码：Adoi:10.3969/j.issn.1000-6281.2021.06.002
Effect of trace Zr on aging hardening and precipitation microstructure of Al-Cu-Mg alloy
JIANG Cheng，REN Shu-qi，LIU Cui-xiu*，SUN Wei*
(Institute of Microstructure and Property of Advanced Materials,Faculty of Materials and Manufacturing, Beijing University of Technology,Beijing 100124，China)
Abstract The effects of trace Zr addition on the age-hardening behavior and the precipitation microstructure of Al-Cu-Mg alloy were investigated by Vickers hardness testing and transmission electron microscopy in this work. The results show that the addition of Zr appears to have little effect on the hardness of the alloy at the initial stage of aging, but has a significant enhancement effect on the hardness of the alloy at the peak-aging stages and over-aging stages. Zr has a high vacancy binding energy and is easy to combine with the vacancies in the alloy matrix, which will limit the precipitation rate of other solute atoms at the initial stage of aging. With the extension of the aging time, the presence of Zr element is conductive to promoting dispersive precipitation of fine S and θ' phases, which increases the peak hardness of the aged alloy significantly. Also, the addition of Zr can effectively suppress excessive coarsening of the θ' phase during the over-aging stage, allowing the θ′ phase to maintain a high diameter-to-thickness ratio, which will effectively improve the hardness and thermal stability of the Al-Cu-Mg alloy.
Keywords Al-Cu-Mg alloy; Zr addition; aging treatment; microstructure; electron microscopy characterization
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