The Mechanical Properties of Single Crystal Diamond

研究的目的是了解晶体缺陷对金刚石力学性能的影响。金刚石被用于各种工业应用，利用它的硬度和耐磨性。在人造金刚石的生长过程中，晶体结构中会掺入缺陷，这些缺陷的浓度取决于生长条件。了解这些缺陷的影响是很重要的，这样就可以为给定的应用程序选择合适的生长方法。使用的方法主要是实验，量化不同类型的金刚石在各种磨损条件下的磨损，并了解其潜在的机制。这方面的一个例子是研究材料受到固体颗粒反复冲击的侵蚀条件下的磨损率。利用各种显微技术研究了质量去除的机制，并研究了点缺陷在这一机制中可能起的作用。目前，我们正在将这些方法扩展到一系列环境条件，如温度升高。为了研究断裂面，还开发了毫米尺寸样品的控制断裂方法。在原子长度尺度上对这些断口表面缺陷的影响正在进行研究，以结合磨损测试结果。我们还与合作者合作，使用高性能计算进行多尺度建模，以研究相同的材料系统。我们希望能够帮助开发和验证这些技术，以便将来可以在其他系统上使用它们。

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.