Anelasticity in thin-shell nanolattices

Area of Science:

• Materials Science
• Mechanical Engineering
• Nanotechnology

Background:

• Periodic three-dimensional (3D) nanolattices with ultrathin shells are engineered materials with unique mechanical properties.
• Understanding their time-dependent deformation is critical for predicting performance and designing applications.

Purpose of the Study:

• To investigate the anelastic deformation behavior of 3D nanolattices with thin shells.
• To elucidate the underlying mechanisms and quantify the extent of anelasticity and recovery.

Main Methods:

• Nanoindentation experiments were performed on 30-nm-thick aluminum oxide nanolattices.
• Finite element analysis (FEA) coupled with diffusion of point defects was employed for modeling.

Main Results:

• Nanolattices exhibited time-dependent deformation under constant load, with anelastic deformation up to 18.1% of elastic deformation.
• Up to 15.7% recovery was observed after unloading, indicating reversible anelastic behavior.
• FEA results qualitatively agreed with experimental data, highlighting the role of point defect diffusion and wavy tube profiles.

Conclusions:

• Anelastic deformation in these nanolattices is attributed to reversible point defect diffusion driven by stress gradients.
• The findings provide insights into the time-dependent mechanical response of nanolattice materials.
• This understanding has implications for developing nanolattices for energy dissipation applications.