Mechanical properties and thermal stability of nanocrystallized pure aluminum produced by surface mechanical attrition treatment
Mechanical properties and thermal stability of nanocrystallized pure aluminum produced by surface mechanical attrition treatment
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DOI：
10.1016/j.msea.2015.03.068
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发表时间：
2015-06-11
期刊：
影响因子：
6.4
通讯作者：
Lu, Jian
中科院分区：
文献类型：
--
作者：
Liu, Yong;Jin, Bin;Lu, Jian
通过表面机械磨损处理（SMAT），在纯铝（Al）片材中生成纳米晶表面层。通过 X 射线衍射 (XRD) 和透射电子显微镜 (TEM) 系统地表征了纳米晶表面层的微观结构。结果表明，位错滑移是SIVIAT细化Al晶粒的主要机制。通过单轴拉伸和显微硬度测试来测试其力学性能。 SMAT 后，纳米结构 Al 的屈服强度比粗晶 Al 的屈服强度高出约两倍，但伸长率有所下降。用SIVIAT讨论了Al的显微组织和力学性能之间的关系。此外，与未经 SMAT 的铝样品相比，SMAT 后的铝样品表现出更快的应变硬化速率降低和更弱的应变硬化。此外，通过在155℃至355℃温度范围内的等温和等时退火处理，研究了纳米晶表面层的热稳定性。结果表明，这种Al纳米晶表面层表现出很高的热稳定性，可以保持到275℃。研究了SMAT处理后Al纳米晶粒的生长动力学。 (C) 2015 Elsevier B.V. 保留所有权利。
By means of surface mechanical attrition treatment (SMAT), nanocrystalline surface layers were generated in pure aluminum (Al) sheet. The microstructure of the nanocrystalline surface layer was systematically characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that dislocation slip is the main mechanism for grain refinement of Al with SIVIAT. The mechanical properties were tested by uniaxial tensile and micro-hardness tests. After SMAT, the yield strength of the nanostructured Al was about two times higher than that of the coarse-grained counterpart, with compromise of elongation. The relationship between microstructure and mechanical properties of Al with SIVIAT was discussed. Moreover, the Al sample after SMAT exhibits a much faster strain hardening rate reduction and a weaker strain hardening than the one without SMAT. Furthermore, the thermal stability of the nanocrystalline surface layer was studied by isothermal and isochronal annealing treatments at the temperature range from 155 degrees C to 355 degrees C. It reveals that such nanocrystalline surface layer of Al exhibits high thermal stability, which can be retained up to 275 degrees C. The growth kinetics of nano-sized grain of Al subjected to SMAT was investigated. (C) 2015 Elsevier B.V. All rights reserved.