Effect of nanoglass grain size investigated by a mesoscale variable characteristic strain model

Chih Jen Yeh, Chang Wei Huang, Yu Chieh Lo, Shigenobu Ogata, Ding Yuan Li, Hsuan Teh Hu, Jason Shian Ching Jang

研究成果: 雜誌貢獻期刊論文同行評審


Severe shear localization in metallic glasses (MGs) significantly limits their mechanical performance. Nanoglass (NG), composed of heterogeneous glassy domains created by introducing interfaces into MGs at the nanoscale, could be a promising strategy against severe shear localization, as demonstrated by numerous atomistic simulations. This study introduces a novel mesoscale kinetic Monte Carlo (kMC) model with a variable characteristic strain (VCS) to investigate the grain size effect in NGs. This model captures the complex evolution of shear bands during deformation, revealing a surprising transition from inhomogeneous to homogeneous deformation as the NG grain size decreases to approximately 10 nm. This transition is attributed to the impediment of shear band formation by the small grain size, facilitated by softer interfaces guiding early shear transformation zone (STZ) activities across the entire sample. Furthermore, a progressive reduction of elastic constants simulates the failure response observed in experiments. Our model predicts a critical grain size for the transition in agreement with molecular dynamics simulations and experiments, highlighting its potential for designing NGs with enhanced shear resistance. This mesoscale model enables the investigation of NG deformation with microstructural features on an experimentally-relevant spatial-temporal scale. This paves the way for tailoring NG microstructures to achieve enhanced mechanical performance, and opens new avenues for exploring the influence of interfaces in controlling shear localization.

期刊International Journal of Mechanical Sciences
出版狀態已出版 - 15 3月 2024


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