Simultaneous strengthening and toughening effects in WC-(nanoWC-Co)

Simultaneous hardening and toughening effects were found for WC-(nanoWC-Co) with microWC strengthening particles in nanoWC-Co cermet matrix. The high microhardness of 1683 +/- 176 Hv comparable to that of nanoWC-12Co was attributed to the hardening effect from both microWC particles and nanoWC dispersion in the Co binder phase. The high fracture toughness of 18.9 +/- 4.0 MPa m(1/2), comparable to that of microstructured WC-12Co, resulted from the larger area of the bimodal-sized fracture surface morphology and the crack bridging due to the microsized strengthening WC particles. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.