Molecular dynamics simulation of dynamic stretching of borosilicate glass

Abstract

Sodium borosilicate (NBS) glass is a potential material for high-level radioactive waste storage, with its mechanical properties critical to its stability under deep geological disposal conditions. This study investigates the effects of the K value (SiO₂/B₂O₃ in mole percent), temperature, and strain rate on the Young's modulus, tensile strength, and fracture strain of NBS glass using molecular dynamics simulation. Results show that increasing the K value enhances tensile strength and fracture strain linearly. The transition from elastic to plastic deformation is driven by the conversion of Si-O structures. Young's modulus and tensile strength decrease linearly with rising temperature, but elevated temperatures also induce plastic flow, shifting the fracture behavior from brittle to ductile. Microstructural analysis reveals that higher temperatures accelerate B-O and Si-O structure conversion, increasing the strain needed for plastic deformation. Moreover, higher strain rates improve both Young's modulus and tensile strength.