Accession Number:

ADA250164

Title:

Nanoscale Investigation of Indentation, Adhesion, and Fracture of Diamond (111) Surfaces

Descriptive Note:

Interim rept. 1 Sep 1991-30 Aug 1992

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON DC

Report Date:

1992-04-01

Pagination or Media Count:

27.0

Abstract:

Molecular dynamics simulations have been used to model the dynamics of indentation and the resulting damage for a 111 surface of a 1x1 hydrogen terminated diamond tip interacting with the 111 surface of both a 1x1 hydrogen terminated diamond crystal and a non-hydrogen terminated diamond crystal. In both cases, indentation can result in a non-adhesive i.e. elastic or an adhesive i.e. plastic interaction depending on the maximum value of the applied load. Further, adhesion is usually accompanied by fracture and is independent of where the tip contacts the surface. In the case of the hydrogen terminated crystal, the diamond crystal structure is significantly disrupted as a result of the indentation. When the hydrogen is removed form the crystals surface, adhesion occurs at lower loads than previously observed. However, the crystal structure is not significantly altered as a result of the indentation. The state of the surface dictates the type of indentation mechanism.

Subject Categories:

  • Inorganic Chemistry
  • Geology, Geochemistry and Mineralogy
  • Crystallography
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE