Microstructure of the cBN/WC6Co composite produced by the pulse plasma sintering (PPS) method

摘要

The cBN/WC6Co composite with the relative density of 99.8% and hardness of 2130 HV5 was produced by sintering at a temperature of 1150 degrees C under a pressure of 100 MPa for 5 min. The composite was sintered using electric pulses generated periodically by discharging a capacitor battery. The constituent phases of the composite, as identified by the NBED method, were the cBN, WC, and Co phases. The HR STEM observations have shown that the interfaces between the individual phases are continuous and no pores or precipitates of other phases can be seen there. Thanks to the specific heating realized by electric pulses, the composite is heated during each current pulse to a temperature of 1950 degrees C at a rate of 10(5) degrees C/s. As a result of these quick changes of the temperature, transient thermal compressive stresses of about 3 GPa are induced in the composite, which results in the grains of the WC composite matrix being refined and defected. (C) 2015 Elsevier Ltd. All rights reserved.