Wear modes in slurry jet erosion of tungsten carbide hardmetals: Their relationship with microstructure and mechanical properties

Hardmetals based on tungsten carbide (either with a cobalt binder or cobalt/nickel binder) have been subjected to slurry jet erosion, using silica sand or alumina erodent entrained in a water jet. Wear processes have been identified in a number of hardmetals and results correlated with conventional parameters used for assessing hardmetals (hardness, binder linear intercept, WC grain size). Results were obtained using two principal impingement angles; normal incidence (90 degrees) and 45 degrees, and were correlated with bulk hardness but the relationships that were found differed in detail from those for abrasion. Local microstructure, evidenced by electron microscopy on wear scars and cross-sections, appears to play a more fundamental role in the respect of material response to erodent impact, with WC grain size being a major determinant. The type of erodent used had a significant effect on material response; microscopic plastic grooving occurred readily with an alumina slurry jet, but was not evident in the case of silica sand. 3-D spatial analysis via a confocal optical microscope and also a non-contact scanning eddy current probe of wear scars have also used to characterise their shape and extent of degradation respectively. Crown Copyright (C) 2014 Published by Elsevier Ltd. All rights reserved.