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Updated: Jun 12, 2026

Characterizing Dissipative Elastic Metamaterials Produced by Additive Manufacturing
Published on: June 28, 2024
Flexural phonon instability defines intrinsic van der Waals elastic limits in the interlayer direction
Heyi Wang1, Miaojie Liu2, Jiayi Li1
1Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China.
Abstract:
Frenkel's cohesive model predicts an ideal elastic strain limit of ~10% for strong solids, a bound upheld in conventional materials. We demonstrate that such consistency breaks down in van der Waals (vdW) solids, challenging established strength theories. In situ tensile tests, combined with first-principles calculations, reveal unexpected localized decohesion failure at only ~3% strain in graphite and ~2% in h-BN along the interlayer direction-well below defect-controlled limits-defining their intrinsic elastic limits. This localization phenomenon is absent in MoS2, GaSe, and 3D crystals. We identify flexural phonon instability as the trigger for a cascade of strain localization, creating periodic nanogaps to release elastic strain energy. This dynamic instability redefines the intrinsic elastic limits of vdW crystals and opens pathways to tailor their structural/transport properties via strain engineering.
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