Mg含量对Al-Zn-Mg铝合金组织及性能的影响

doi:10.13251/j.issn.0254-6051.2021.12.016

摘要/Abstract

摘要： 通过改变镁的含量,设计了4种不同成分的Al-6.0Zn-xMg合金。采用光学显微镜(OM)、扫描电镜(SEM)、差式扫描量热分析仪(DSC)、硬度、导电率以及室温拉伸等分析测试方法,研究了Mg含量对Al-Zn-Mg合金铸态、均匀化态组织性能及T6态力学性能的影响。结果表明:4种铸态合金组织晶界附近存在大量共晶网状结构与链状第二相,主要为α(Al)+三元T(AlZnMg)相,合金中还存在少量的Al₃(Zr,Ti)相和富铁相,提高Mg含量会使合金组织中的非平衡共晶相增加。合金均匀化处理后空冷,基体内有大量细小弥散的针状η(MgZn₂)相析出,且随着Mg含量的提高,这种针状η(MgZn₂)相的析出数量也逐渐增多。随着Mg含量增加,硬度逐渐增加,导电率逐渐下降,且均匀化态合金的硬度及导电率比铸态的高。4种T6态合金中Al-6.0Zn-2Mg合金的综合力学性能最佳。

关键词: Mg含量, Al-Zn-Mg合金, 铸态组织, 均匀化组织, T6态, 力学性能

Abstract: By changing the magnesium content, four compositions of Al-6.0Zn-xMg alloys were designed. The effect of Mg content on microstructure and properties of the as-cast and homogenized Al-Zn-Mg alloy and T6 state properties was studies by means of optical microscope (OM), scanning electron microscope (SEM), differential scanning calorimetry (DSC), hardness, electrical conductivity and room temperature tensile tests. The results show that there are a large number of eutectic network structures and chain-like second phases near the grain boundaries of the four as-cast alloys, mainly α (Al)+ternary T (AlZnMg) phases, and a small number of Al₃ (Zr, Ti) phases and iron-rich phases, and increasing the Mg content will increase the non-equilibrium eutectic phase in the alloy structure. After homogenization treatment and followed air-cooling, a large number of fine and dispersed needle-like η(MgZn₂) phases are precipitated in the alloy matrix, and with the increase of Mg content, the number of precipitation of this needle-like η(MgZn₂) phase also gradually increases. As the Mg content increases, the hardness gradually increases, while the electrical conductivity gradually decreases, and the hardness and electrical conductivity of the homogenized alloy are higher than that of the as-cast alloy. Among the four alloys at T6 state, the Al-6.0Zn-2Mg alloy has the best comprehensive mechanical properties.

Key words: Mg content, Al-Zn-Mg alloy, as-cast microstructure, homogenized microstructure, T6 state, mechanical properties

中图分类号:

TG146.2

黄元春, 李湘粤, 谭维杨, 胡嘉伟, 黄娟, 邹倜. Mg含量对Al-Zn-Mg铝合金组织及性能的影响[J]. 金属热处理, 2021, 46(12): 100-106.

Huang Yuanchun, Li Xiangyue, Tan Weiyang, Hu Jiawei, Huang Juan, Zou Ti. Effect of Mg content on microstructure and properties of Al-Zn-Mg aluminum alloy[J]. Heat Treatment of Metals, 2021, 46(12): 100-106.

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