Damage of nuclear graphite and structural response of carbon fibre to tension

This thesis examines the structural changes in carbon fibres and nuclear graphite caused by tensile testing, industrial machining, and ion irradiation using Raman spectroscopy. The results show that there is a linear trend in the G peak position shift and ratio of D peak to G peak with increasing tensile strain, and molecular dynamics simulations provide a clear understanding of the structural changes. Additionally, the study found that industrial machining creates an abrasion layer with residual compressive stress reaching as high as 1 GPa, characterised by variations in the ratio of D peak to G peak and a rapid drop in crystallite size. The implantation of gold ions also resulted in a significant growth of the ratio of D peak to G peak and compressive stress on the graphite surface.

The comprehensive understanding of the connection between Raman spectroscopy and the properties of carbon materials provided by this thesis has important implications for further studies and industrial manufacturing of nuclear graphite. The results of the tensile testing, industrial machining, and ion irradiation experiments improve our understanding of the behaviour of carbon materials in nuclear power plants and the conditions that affect their properties. This information can contribute to the optimisation of industrial manufacturing processes and the development of new technologies for the use of carbon materials in nuclear power plants.