JOURNAL OF MATERIALS PROCESSING TECHNOLOGY, vol.183, pp.234-240, 2007 (SCI-Expanded)
Cemented carbide tools are widely used in machining industry due to their superior properties. Laser processing of the tool surface provides thermal integration of binding agent with carbide compounds in the surface region. This in turn improves the microstructure in the region irradiated by the laser beam. In the present study, laser heating of cemented carbide tool surface is carried out. Temperature field in the irradiated region is obtained and temperature gradients as well as cooling rates in the surface region are predicted. Microstructural analysis prior and after the laser heated surface carried out. Fracture toughness of the laser treated surface is measured using indentation tests. It is found that Co and TaC melt in the early heating period due to their relatively lower thermal conductivity than WC. High cooling rates and temperature gradients below the surface are responsible for high thermal stresses developed in this region. Multi directional cracks are observed at the surface and formation of tungsten nitride (WN) occurs in the surface region as illustrated by XRD measurements. (c) 2006 Elsevier B.V. All rights reserved.