Atomistic Simulations of Dislocation - Crack Interaction

Atomistic study of dislocation loop emission from a crack tip.

We report the first atomistic calculation of the saddle-point configuration and activation energy for the nucleation of a 3D dislocation loop from a stressed crack tip in single crystal Cu. The transition state is found using reaction pathway sampling schemes, the nudged elastic band, and dimer methods. For the (111)[110] crack, loaded typically at 75% of the athermal critical strain energy rel...

Predicting dislocation climb: Classical modeling versus atomistic simulations

Atomistic study of crack-tip cleavage to dislocation emission transition in silicon single crystals.

At low temperatures silicon is a brittle material that shatters catastrophically, whereas at elevated temperatures, the behavior of silicon changes drastically over a narrow temperature range and suddenly becomes ductile. This brittle-to-ductile transition has been observed in experimental studies, yet its fundamental mechanisms remain unknown. Here we report an atomistic-level study of a funda...

The Interaction between a Dislocation and a Crack: Closure Considerations

The interaction between an edge dislocation and a crack in the presence of uniform applied tension and shear is considered. Emphasis is placed on the effects of partial closure and crack-face friction. Representative results are given.

Atomistic simulations of calcite nanoparticles and their interaction with water.

Molecular dynamics (MD) simulations have been used to study the stability of calcite nanoparticles ranging in size from 18 to 324 f.u., both in vacuo and in the presence of explicit water molecules. In vacuo, the smallest particles become highly disordered during the MD simulation due to rotation and translation of the undercoordinated CO(3) (2-) anions at the edges of the particles. As the nan...