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

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 (Lambda = 1.06 Mym) with different energy densities. The high-temperature Beta-WCz phase (stable above 2500 degree C) was frozen without any decay in Alpha-WC and W2C. The strict stoichiometry of Alpha-WC up to high temperatures is shown, because the observed changes 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 square millimeters down to 0.04 square millimeters, the advantages of both a position-sensitive detector and a microdiffractometer connected to an annular proportional counter, were used.