First-Principles Modeling of Mechanics and Chemistry of Materials
Abstract
Silica (SiO2) glass is one of the essential materials in human civilization for making household items, window panes, lenses and optical fibers. An important reason for its wide adaptation is its formability near the glass-transition temperature (Tg > 1100 deg C). Si02 glass at room temperature, however, is usually brittle due to fracture instability. But when the "brittle" glass is confined in extremely small dimensions at tens of nanometres, the nature of flow and fracture may change. Newest experiments performed at Sandia Center for Integrated Nanotechnologies (CINT) show that glass nanowires with diameters less than 20 nm can become ductile at room temperature, with surprisingly large tensile plastic elongations up to 18% (Luo et al., submitted for review in Nature). Remarkably, these ductile glass nanowires also possess high flow strengths, and are thus much more energy-absorbing and damage-tolerant than expected. Atomistic modeling indicates that the unexpected ductility is due to the development of a surface affected zone in the nanowires, which enhances ductility by producing more bond-switching events per irreversible bond loss.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 22, 2009
- Accession Number
- ADA501824
Entities
People
- Ju Li
Organizations
- Ohio State University