Analysis of residual stresses and wear mechanism of HF-CVD diamond coated cemented carbide tools

Chemical vapour deposition (CVD) diamond coated tools have demonstrated their potential for the machining of difficult to machine materials in the last 10 years. The lack of adequate coating adhesion in many cases remains an issue and often leads to spontaneous coating delamination and sudden tool failure however. The work described in this paper was undertaken with the aim of understanding the influence of residual stresses and coating quality on the coating adhesion during the machining of aluminium alloys. Residual stresses were determined using Raman spectroscopy as well as X-ray diffraction analysis and a comparison of the results obtained using the two methods is given. Raman spectroscopy was also implemented to analyse the coating quality. Furthermore, the failure mechanism of CVD diamond coated tools was studied using cross-sections prepared by focused ion beam sputtering.