In this work, we investigate the anelastic deformation behavior of periodic three-dimensional (3D) nanolattices with extremely thin shell thicknesses using nanoindentation. The results show that the nanolattice continues to deform with time under a constant load. In the case of 30-nm-thick aluminum oxide nanolattices, the anelastic deformation accounts for up to 18.1% of the elastic deformation for a constant load of 500 μN. The nanolattices also exhibit up to 15.7% recovery after unloading. Finite element analysis (FEA) coupled with diffusion of point defects is conducted, which is in qualitative agreement with the experimental results. The anelastic behavior can be attributed to the diffusion of point defects in the presence of a stress gradient and is reversible when the deformation is removed. The FEA model quantifies the evolution of the stress gradient and defect concentration and demonstrates the important role of a wavy tube profile in the diffusion of point defects. The reported anelastic deformation behavior can shed light on time-dependent response of nanolattice materials with implication for energy dissipation applications.

中文翻译：

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薄壳纳米晶格中的滞弹性

在这项工作中，我们使用纳米压痕研究了具有极薄壳厚度的周期性三维 (3D) 纳米晶格的滞弹性变形行为。结果表明，纳米晶格在恒定负载下随时间持续变形。对于 30 nm 厚的氧化铝纳米晶格，在 500 μN 的恒定载荷下，滞弹性变形占弹性变形的 18.1%。纳米晶格在卸载后还表现出高达 15.7% 的恢复率。进行了结合点缺陷扩散的有限元分析 (FEA)，这与实验结果定性一致。滞弹性行为可归因于存在应力梯度时点缺陷的扩散，并且在消除变形时是可逆的。FEA 模型量化了应力梯度和缺陷浓度的演变，并证明了波浪管剖面在点缺陷扩散中的重要作用。所报道的滞弹性变形行为可以阐明纳米晶格材料的时间依赖性响应，并暗示能量耗散应用。