Investigation on deformation behavior of non-crystalline materials via molecular dynamics simulations

Abstract

This method enables the calculation of viscosity from high to room temperature, where the extracted activation energy of isostructural flow is found to be correlated with Poisson’s ratio, the signature of intrinsic toughness. Next, we designed several toughening strategies for intrinsically brittle glasses such as silica, aluminosilicate, and model metallic glasses. The enhanced toughness for silica and aluminosilicate glasses is achieved by introduced structural and/or chemical heterogeneities via consolidating glassy nanoparticles. We also observed surprising work hardening ability, which is attributed to the stress-facilitated relaxation of plasticity carriers (over-coordinated clusters). In addition, we also designed strong, ductile, and work hardenable composites with exclusively brittle glassy constituents by exploiting stiffness contrast and size effects. Finally, we revealed the tensile plasticity of brittle and ductile glassy nanowires display distinct strain-rate dependency due to the ductile glass possesses more hierarchical fractal potential energy landscape. Our results shed light on how to obtain tough glasses both intrinsically and extrinsically via providing atomic insights.

Amorphous solids such as oxide and metallic glasses feature intriguing mechanical, optical, thermal, and chemical properties, therefore are widely used in energy, electronic, and engineering applications. However, both the structural and functional applications are largely restricted by the brittleness and poor toughness. Therefore, the underlying mechanisms governing the design of intrinsically tough glasses, the development of efficient toughening strategies for brittle glasses, and the strain-rate effect on toughness, are needed to be uncovered by providing atomic insights using molecular dynamics simulations.Here, we first revealed the intrinsic correlation between shear modulus and viscosity for both supercooled liquids and glasses, with which a novel viscosity calculation method is developed.