Quantifying the Defect Character of Grain Boundaries with Traction-based Descriptors
Abstract
Interfaces are ubiquitous in a wide range of natural and engineering materials, and affect many of the mechanical properties. It is well accepted that the grain boundary interfaces control the strength and ductility of nanostructured materials. The objectives of this research is to develop traction- or stress-based grain boundary descriptors to bridge the gap between the defect character at the boundary and the underpinning stress-controlled deformation mechanisms. Such descriptors will ultimately pave the way towards: (a) detailed understanding of the unit mechanisms associated with the relevant defect type at the grain boundary, and (b) the development of predictive models at the meso-scale to quantitatively assess the contribution of such defects to the strength and ductility of the nanostructured material. In this 4-year research project, we have (1) constructed novel grain boundary descriptors for twisted heterogeneous atomic-sheet interfaces, which has enabled the controlled nanomanufacturing of these 2D sheets, (2) extended the notion of local atomistic stress as defined by virial theorem beyond the MD domain, to elucidate the local stress states of grain boundaries modeled in DFT calculations or imaged in a TEM, and (3) obtained a dislocation representation of low- to high tilt-angle grain boundaries from the local atomistic stress fields for direct meso-scale modeling of these boundaries in discrete dislocation dynamics simulations.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 2023
- Accession Number
- AD1231162
Entities
People
- Huck Beng Chew
Organizations
- University of Illinois Urbana–Champaign