Measurement of residual thermal stress in WC–Co by neutron diffraction

The temperature dependence of residual stresses in a WC-17.8vol.%Co cemented carbide was measured by neutron diffraction. The comparison of the WC lattice parameter within the WC-Co and within stress-free WC reference provides a measurement of lattice elastic strains and, using Hooke's law, stresses. WC is found to be under hydrostatic compressive stresses of about -400 MPa at room temperature, which decrease monotonically with temperature to a near-zero value at 800 degrees C. Residual stresses in cobalt also decrease with increasing temperature, but show an apparent increase above 800 degrees C, which is attributed to an increase in lattice parameter due to W dissolution in the Co phase. (C) 2008 Elsevier Ltd. All rights reserved.