Effect of Mo2C addition on the microstructures and mechanical properties of WC-SiC ceramics

摘要

Mo2C was added to WC-4.85 mol% SiC ceramics and sintered at 1600 degrees C using a resistance-heated hot-pressing machine. Dense ceramics containing 0-3 mol% Mo2C were obtained. The reaction products (W, Mo)(5)Si-3 and (W, Mo)Si-2 were produced during sintering. The relative amounts of (W, Mo)Si-2 decreased and (W, Mo)(5)Si-3 increased with increasing Mo2C amount. The abnormally-grown plate-like WC grains formed for WC-4.85 mol% SiC ceramics below 1.5 mol% Mo2C. Above 2 mol% Mo2C, the ceramics had a fine, equiaxed granular structure. The average WC grain size decreased from 0.77 mu m without Mo2C, to 0.50 mu m above 2 mol% Mo2C. The Vickers hardness increased with increasing Mo2C amount, reaching 21.4 GPa at 2 mol% MO2C. The hardness of the WC-4.85 mol% SiC ceramics correlated with the inverse square root of the WC grain size. The fracture toughness for the Mo2C-added WC-4.85 mol% SiC ceramics ranged from 7.1 to 7.8 MPa m(0.5) (C) 2017 Elsevier Ltd. All rights reserved.