Co removal and phase transformations during high power diode laser irradiation of cemented carbide

▶ Use of a continuous wave-high power diode laser to remove surface Co-binder from Co-cemented tungsten carbide. ▶ Study of phase transformations and micro-structural modifications of the WC-Co substrates by varying the energy density during laser processing. ▶ Increasing the energy density, the micro-structure of the WC-Co is progressively transformed, with the removal of Co and the formation of larger grains. ▶ At very high energy density, local melting of the WC grains with the formation of big agglomerates of interlaced grains is observed. ▶ Crystalline structure of the irradiated substrate shows the presence of a brittle ternary eutectic phase of W, Co and C, detrimental to the mechanical properties of WC-Co.