Mechanical properties of unidirectional nanoporous gold under compression
Mechanical properties of unidirectional nanoporous gold under compression
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DOI：
10.1016/j.actamat.2022.118078
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发表时间：
2022-06
期刊：
影响因子：
9.4
通讯作者：
Yefeng Zhang;L. Zou;Ling-Zhi Liu;H. Xie;Cuiqin Li;H. Jin
中科院分区：
文献类型：
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作者：
Yefeng Zhang;L. Zou;Ling-Zhi Liu;H. Xie;Cuiqin Li;H. Jin
在相同孔隙度下，合金纳米多孔金属的强度比传统多孔金属高一个数量级以上。然而，随机结构NP金属在实践中的优势受到其网络结构机械效率低的限制。本文报道了一种具有单向孔道的各向异性纳米孔金（NPG）在合金化过程中也能自组织。这种材料结合了机械高效的拓扑结构和超强的纳米级固体骨架。因此，其面外平均强度（461±52 MPa）是以往研究中最强npg的两倍多。由于结构的各向异性，单向npg在压缩下通过扭结带的形成和扩展而变形，而不是之前大多数npg的均匀致密化。孔道错位和孔壁空隙等缺陷可能会降低宏观强度，导致实测强度差异较大，理论与实验数据存在差距。我们预计，未来通过优化合金化参数，单向npg的组织和力学性能将得到进一步改善。金属孔壁相的高强度、单向孔通道和优异的导热性和导电性可能使这种材料在许多领域得到新的应用。
Dealloyed nanoporous (NP) metals are expected to be stronger by more than one order of magnitude than conventional porous metals of same porosity. However, the strengths of random-structured NP metals in practice are limited by the low mechanical efficiency of their network structure. In this paper, we report that an anisotropic nanoporous gold (NPG) with unidirectional pore channels can also be self-organized in dealloying. This material combines a mechanically efficient topology structure with ultra-strong nanoscale solid skeleton. In consequence, its out-of-plane mean strength (461±52 MPa) is more than twice that of the strongest NPGs reported in previous studies. Because of the structural anisotropy, unidirectional NPGs deform by the formation and expansion of kink bands under compression, unlike the uniform densification of most previous NPGs. The pore-channel misalignment and other defects such as the voids in pore walls may have reduced macroscopic strength, which accounts for a large scatter in the measured strength and a gap between theoretical and experimental data. We anticipate that the structure and mechanical properties of unidirectional NPGs will be further improved in the future by optimizing dealloying parameters. A combination of high strength, unidirectional pore channels, and excellent thermal and electrical conductivity of metallic pore-wall phase might enable novel applications of this material in many areas.