The influence of heat treatments on the microstructure and the mechanical properties in commercial 7020 alloys
The influence of heat treatments on the microstructure and the mechanical properties in commercial 7020 alloys
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DOI：
10.1016/j.msea.2014.12.040
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发表时间：
2015-02-25
期刊：
影响因子：
6.4
通讯作者：
Reimers, W.
中科院分区：
文献类型：
--
作者：
Paulisch, M. C.;Wanderka, N.;Reimers, W.
研究了不同热处理工艺对挤压态7020铝合金微观组织的影响，并由此对挤压态7020铝合金的宏观性能产生影响。利用光学显微镜和电子背散射衍射相结合的晶粒形态和织构分析的微观结构的发展进行了分析。此外，扫描电子显微镜，透射电子显微镜和三维原子探针研究了不同的沉淀物的形成，形貌和化学成分。显微组织状态与压缩和拉伸试验结果相关。三维原子探针分析表明，工业7020合金中的Guinier-Preston区的化学成分为Al 6 MgZn，Cu含量较低。附加元素Fe、Mn和Cr对Guinier-Preston带的化学成分没有任何影响。由于不同的热处理，已经确定了析出物的尺寸和分布的变化，这导致机械性能的显着差异。通过结合挤压工艺和专用的人工时效，可以将断裂伸长率提高到15.0%，UTS提高到460 MPa。(C)© 2014 Elsevier B. V.保留所有权利。
The influence of different heat treatments on the microstructure and hence the macroscopic properties of extruded commercial 7020 alloys is investigated. The development of the microstructure was analysed using a combination of optical microscopy and electron backscatter diffraction for analysing the grain morphology and texture. Furthermore scanning electron microscopy, transmission electron microscopy and three dimensional atom probe were applied to investigate the formation, morphology and chemical composition of the different precipitates. The microstructural conditions are correlated with the results of the compression and tensile test. The analyses by the three dimensional atom probe reveals that the Guinier-Preston zones in the commercial 7020 have the chemical composition Al6MgZn with additional low Cu contents. The additional elements Fe, Mn and Cr do not have any influence of the chemical composition of the Guinier-Preston zones. Due to the different heat treatments changes in the size and distribution of the precipitates have been determined, which leads to remarkable differences in the mechanical properties. By combining the extrusion process and a dedicated artificial aging it was possible to increase the elongation at fracture up to 15.0% and the UTS up to 460 MPa. (C) 2014 Elsevier B.V. All rights reserved.