The Mechanical Properties of Single Crystal Diamond

The aim of the research is to understand the effects of crystal defects on the mechanical properties of diamond. Diamond is used in a variety of industrial applications that exploit its hardness and resistance to wear. During the growth of synthetic diamond, defects are incorporated into the crystal structure and the concentration of these defects depends of the growth conditions. It is important to know the effects these defects are having so that the growth method can be chosen appropriately for a given application.

The methods used are principally experiments quantifying the wear of different types of diamond under a variety of wear conditions and understanding the underlying mechanism. An example of this is the study of the wear rate under erosive conditions where the material is subjected to repeated impacts from solid particles. The mechanisms for mass removal have been studied using a variety of microscopic techniques and the potential role point defects can play in this mechanism has been investigated. We are currently extending these methods to a range of environmental conditions such as raised temperatures.
Methods for the controlled fracture of millimetre sized samples have also been developed for the purpose of studying fracture surfaces. The effects of defects on these fracture surfaces at an atomic length scale is being investigated to tie in to wear test results.

We are also working with collaborators carrying out multiscale modelling using high performance computing to study the same material system. We hope to be able to help develop and validate those techniques so they can be used on other systems in future.