Grain boundary segregation and intermetallic precipitation in coarsening resistant nanocrystalline aluminum alloys
Grain boundary segregation and intermetallic precipitation in coarsening resistant nanocrystalline aluminum alloys
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DOI：
10.1016/j.actamat.2018.09.038
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发表时间：
2019-02-15
期刊：
影响因子：
9.4
通讯作者：
Rohatgi, A.
中科院分区：
文献类型：
--
作者：
Devaraj, A.;Wang, W.;Rohatgi, A.
尽管纳米晶材料具有所有独特的性质，但它们对热诱导的颗粒粗化的敏感性是臭名昭著的，从而对其应用温度施加了上限。在这项研究中，我们展示了一种耦合的蒙特卡罗-分子动力学模拟指导的实验方法，以提高轻质纳米晶Al-Mg合金的抗热诱导晶粒粗化能力。用平面图、横截面扫描电子显微镜和原子探针法对Al-Mg合金的组织、晶界偏析和粗化程度进行了表征。粗化阻力是通过控制镁偏析对晶界的热力学稳定和通过用纳米金属间化合物钉扎晶界的动力学稳定相结合的结果。因此，我们强调了通过补充热力学和动力学稳定化方法来扩大纳米晶合金应用温度上限的机会。(C)2018 Acta Materialia Inc.由Elsevier Ltd.出版。保留所有权利。
In-spite of all of the unique properties of nanocrystalline materials, they are notorious when it comes to their susceptibility to thermally induced grain coarsening, thus imposing an upper limit to their application temperature. In this study, we demonstrate a coupled Monte Carlo-molecular dynamics simulation-guided experimental approach of improving the resistance to thermally induced grain coarsening in light-weight nanocrystalline Al-Mg alloys. The structure, grain boundary segregation of Mg, and extent of grain coarsening of the Al-Mg alloys were characterized using plan view and cross-sectional scanning transmission electron microscopy and atom probe tomography. Coarsening resistance is attributed to a combination of thermodynamic stabilization of grain boundaries by controlled Mg segregation, and kinetic stabilization through pinning of the boundaries with nanoscale intermetallic precipitates. Thus, we highlight the opportunities in extending the upper limit of application temperature for nanocrystalline alloys by using a complementary thermodynamic and kinetic stabilization approach. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.