Atomistic explanation of shear-induced amorphous band formation in boron carbide

Loading...
Thumbnail Image

Authors

An, Qi
Goddard III, William A.
Cheng, Tao

Issue Date

2014

Type

Article

Language

Keywords

Research Projects

Organizational Units

Journal Issue

Alternative Title

Abstract

Boron carbide (B4C) is very hard, but its applications are hindered by stress-induced amorphous band formation. To explain this behavior, we used density function theory (Perdew-Burke-Ernzerhof flavor) to examine the response to shear along 11 plausible slip systems. We found that the (0111)/<1101> slip system has the lowest shear strength (consistent with previous experimental studies) and that this slip leads to a unique plastic deformation before failure in which a boron-carbon bond between neighboring icosahedral clusters breaks to form a carbon lone pair (Lewis base) on the C within the icosahedron. Further shear then leads this Lewis base C to form a new bond with the Lewis acidic B in the middle of a CBC chain. This then initiates destruction of this icosahedron. The result is the amorphous structure observed experimentally. We suggest how this insight could be used to strengthen B4C.

Description

Citation

Publisher

American Physical Society

License

In Copyright

Journal

Volume

Issue

PubMed ID

ISSN

0031-9007

EISSN

Collections