X-ray diffraction study of small laser-treated spots on WC-Co hardmetal

Abstract

The influence of laser treatment on phase transformation and stability of WC-6%Co hardmetal was investigated by X-ray diffraction. The sample was irradiated by a neodymium-glass laser (λ=1.06 μm) with different energy densities. The high-temperature β-WC_z phase (stable above 2500 °C) was frozen without any decay in α-WC and W₂C. The strict stoichiometry of α-WC up to high temperatures is shown, because the observed changes in lattice parameters could be attributed to different residual stress states. Therefore, the nondilated direction method was used. The degree of decarburization in the laser spot has been estimated. To obtain material information about regions of 3 mm² down to 0.04 mm², the advantages of both a position-sensitive detector and a microdiffractometer connected to an annular proportional counter, were used.