This study applies nanoindentation and other analysis techniques to investigate the influence of wire electrical discharge
machining (EDM) process on the structure and properties of machined surface layers of WC/Co composites. Multiple indents were
conducted on the cross-section of the surface recast layer, sub-surface heat-affected zone, and bulk material. The energy disperse Xray
spectrometry and X-ray diffraction were used to analyze the material compositions in the heat-affected zone and recast layer and
to study the electrical spark eroded surface. The indents were inspected by scanning electron microscopy to distinguish between
regular and irregular indents in these three regions. Irregular indents were caused by the porosity, soft matrix material, separation of
grain boundaries, and thermal cracks caused by EDM process. The hardness and modulus of elasticity obtained from regular
indents in bulk material and heat-affected zone were comparable to those of WC. It was found that the recast layer had lower
hardness and modulus of elasticity than the bulk material and heat-affected zone.
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