3D imaging of structures in bulk and surface modified WC-Co hardmetals

Characterisation of WC-Co hardmetals using a focused ion beam scanning electron microscope (FIB-SEM) allows the three dimensional reconstruction of the microstructure and direct measurements of microstructural features such as binder phase, volume fraction and carbide grain size/shape. Using a FIB-SEM, 3D phase maps of WC-Co were created and EBSD used to identify individual grains and grain boundaries. Conventional 2D measurements have been compared with those from 3D datasets to evaluate both the reliability and extra information available with the FIB-SEM. Additionally the FIB SEM has been used to produce multiple sequential cross-sections of hardmetal surfaces modified by commonly used processing methods such as grinding or electro-discharge machining. This has enabled characterisation of the extent of sub surface defects and microstructural damage introduced by these processes with much greater clarity than normal 2D sectioning methods.