The influence of natural aging and repeated solution annealing on microstructure and mechanical properties of hot extruded alloys Al 7020 and Al 7175
The influence of natural aging and repeated solution annealing on microstructure and mechanical properties of hot extruded alloys Al 7020 and Al 7175
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DOI：
10.1016/j.msea.2017.10.048
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发表时间：
2018-01
期刊：
影响因子：
6.4
通讯作者：
M. Paulisch;A. Treff;I. Driehorst;W. Reimers
中科院分区：
文献类型：
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作者：
M. Paulisch;A. Treff;I. Driehorst;W. Reimers
本研究着重于自然时效和重复固溶退火对两种不同的7xxx铝合金的显微组织和力学性能的影响。对7020和7175合金进行热挤压，并在室温下自然时效18个月。然后在自然老化条件下和三种不同的重复固溶退火过程后分析股线。在第三步中，对它们进行峰值时效，然后分析它们的微观结构和机械性能。对于微观结构的分析，光学，扫描和透射电子显微镜以及电子背散射衍射的组合已被使用。通过压缩和拉伸试验测量了力学性能。从这些研究中可以得出以下几个结论：1.反复固溶退火影响股线表面的晶粒形态。2. 7175合金在多次固溶退火过程中形成了Al2CuMg和Al12Mg2Cr2颗粒。3.在重复固溶退火和随后的峰值时效条件下的试样表现出比自然时效和随后的峰值时效合金更低的拉伸强度值。4.重复固溶退火和自然时效都不会使峰值时效材料的断裂伸长率恶化，这对于工业来说是一个很大的优势。
This investigation focusses on the influences of natural aging and repeated solution annealing on the microstructure and the mechanical properties of two different 7xxx Al-alloys. The alloys 7020 and 7175 were hot extruded and naturally aged at room temperature for 18 month. The strands were then analyzed in naturally aged condition and after three different repeated solution annealing processes. In a third step they were peak aged and then analyzed regarding their microstructure and mechanical properties. For the analysis of the microstructure a combination of optical, scanning and transmission electron microscopy as well as electron backscatter diffraction has been used. The mechanical properties were measured by compression and tensile tests. Several results can be concluded from these investigations: 1. The repeated solution annealing is affecting the grain morphology at the surface of the strands. 2. In alloy 7175 Al2CuMg and Al12Mg2Cr2particles were formed during the repeated solution annealing processes. 3. Specimens in the repeated solution annealed and subsequent peak aged condition exhibit lower tensile strength values than the naturally aged and subsequent peak aged alloys. 4. Neither repeated solution annealing nor natural aging is deteriorating the elongation at fracture of the peak aged material, which is a great advantage for the industry.