A novel aluminum based nanocomposite with high strength and good ductility
A novel aluminum based nanocomposite with high strength and good ductility
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DOI：
10.1016/j.jallcom.2015.07.088
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发表时间：
2015-11-15
影响因子：
6.2
通讯作者：
Shokouhimehr, Mohammadreza
中科院分区：
文献类型：
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作者：
Ramezanalizadeh, Hossein;Emamy, Masoud;Shokouhimehr, Mohammadreza
通过机械铣削和热挤压技术制备了含有纳米 Al3Mg2 增强材料的铝基纳米复合材料。为此，将 Al 和 Al3Mg2 粉末机械混合并在不同时间（0、2、5、7、10、15 和 20 小时）进行研磨，以获得 Al-10 wt.% Al3Mg2 复合粉末。冷压粉末的热挤压在400℃下进行，挤压比为6:1。使用透射电子显微镜、扫描电子显微镜和X射线衍射研究了粉末和固结材料的微观结构。还通过配备 EDS 分析仪的扫描电子显微镜研究了断裂表面。结果表明，与Al基体的晶格应变不同，球磨时间的增加导致晶粒尺寸减小。此外，随着球磨时间的增加，制备的复合材料表现出均匀分布和更少的 n-Al3Mg2 团聚。通过硬度和拉伸测试研究了这些纳米复合材料的机械行为，结果表明其强度是传统铝的四倍，并且具有良好的延展性。研究发现，随着研磨时间增加至 15 小时，纳米复合材料的极限拉伸强度 (UTS) 和伸长率显着提高。这种改进归因于 n-Al3Mg2 的晶粒细化强化和均匀分布。断口表面表明，随着铣削时间的增加，Al 和 Al3Mg2 之间的界面结合得到改善。界面的 HRTEM 结果表明，界面干净，基体与第二相之间接触紧密。通过将铣削过程延长至 20 小时，由于铣削过程的完成以及复合材料在较高铣削时间内的动态和静态恢复，材料的机械性能没有显着改善。 (C) 2015 Elsevier B.V. 保留所有权利。
Aluminum based nanocomposite containing nano-sized Al3Mg2 reinforcing was fabricated via mechanical milling followed by hot extrusion techniques. For this, Al and Al3Mg2 powders were mixed mechanically and milled at different times (0, 2, 5, 7, 10, 15 and 20 h) to achieve Al-10 wt.% Al3Mg2 composite powders. Hot extrusion of cold pressed powders was done at 400 degrees C with extrusion ratio of 6:1. Microstructures of the powders and consolidated materials were studied using transmission electron microscopy, scanning electron microscope and X-ray diffraction. Fracture surfaces were also investigated by scanning electron microscopy equipped with EDS analyzer. The results showed that an increase in milling time caused to reduce the grain size unlike the lattice strain of Al matrix. In addition, the fabricated composites exhibited homogeneous distribution and less agglomerations of the n-Al3Mg2 with increasing milling time. The mechanical behavior of these nanocomposites was investigated by hardness and tensile tests, which revealed it has four times the strength of a conventional Al along with good ductility. It was found that the ultimate tensile strength (UTS) and elongation of the nanocomposites were significantly improved with increases in milling time up to 15 h. This improvement was attributed to the grain refinement strengthening and homogeneous distribution of the n-Al3Mg2. Fracture surfaces showed that the interfacial bonding between Al and Al3Mg2 could be improved with increasing in milling time. Also HRTEM results from interface showed that a metallurgical clean interface and intimate contact between matrix and second phase. By extending the milling process up to 20 h, there was no significant improvement in mechanical behavior of materials, due to the completion of milling process and dynamic and static recovery of composite at higher milling times. (C) 2015 Elsevier B.V. All rights reserved.