The Mechanical Properties of Single Crystal Diamond

这项研究的目的是了解晶体缺陷对钻石机械性能的影响。钻石被用于各种工业应用，利用其硬度和耐磨性。在人造金刚石的生长过程中，晶体结构中存在缺陷，缺陷的浓度取决于生长条件。重要的是要知道这些缺陷的影响，以便为特定的应用选择适当的生长方法。所使用的方法主要是实验，量化不同类型的钻石在各种磨损条件下的磨损情况，并了解其根本机制。这方面的一个例子是研究材料在腐蚀条件下的磨损率，其中材料受到固体颗粒的反复冲击。用各种微观技术研究了质量去除的机理，并研究了点缺陷在这一机理中可能起的作用。我们目前正在将这些方法扩展到一系列环境条件，如温度升高。为了研究断口表面，我们还开发了控制毫米级样品断裂的方法。这些断口上的缺陷在原子长度尺度上的影响正在被研究，以与磨损测试结果相一致。我们还与使用高性能计算进行多尺度建模的合作者合作，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.