Designing microcompression experiments for nanoporous metals via computational plasticity

Micropillar compression testing is essential for understanding bulk metal plasticity at small scales and has emerged as a key technique for evaluating nanoporous metals like nanoporous gold (NPG). To support experimental design, we present a computational plasticity study on single crystal NPG micropillars, systematically examining four extrinsic factors: pillar height-to-diameter ratio (1.5 ≤ ℎ∕𝑑 ≤ 2.5), taper angle (0 ≤ 𝜃 ≤ 4◦), friction coefficient (0.0 ≤ 𝜇 ≤ 0.2), and misalignment angle (0 ≤ 𝛼 ≤ 2◦). The study reveals that NPG exhibits similar trends to its bulk counterpart but is less prone to post-yield buckling in unstable crystal orientations. For optimal NPG pillar stability, an aspect ratio of 1.5 ≤ ℎ∕𝑑 ≤ 2 is recommended and a moderate taper angle (𝜃 ≈ 2◦) to prevent artificial stiffening and yielding. Even minimal friction (𝜇 ≈ 0.05) enhances stability, while buckling is mainly governed by misalignment, requiring 𝛼 ≤ 1◦ to also avoid underestimating the elastic modulus.

Subjects

Finite element method

Microcompression

Micromechanics

Nanoporous gold

Plasticity

DDC Class

620.1: Engineering Mechanics and Materials Science

Publication version

publishedVersion

Lizenz

https://creativecommons.org/licenses/by/4.0/

Name

1-s2.0-S0264127525009700-main.pdf

Type

Main Article

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2.98 MB

Format

Adobe PDF

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Designing microcompression experiments for nanoporous metals via computational plasticity