Effect of VC Content on Microstructure and Mechanical Properties of WC-VC/WC-TiC Laminated Ceramics

Abstract

WC-VC/WC-TiC (WV/WT) laminated ceramics with different VC contents were prepared by the layer-making and vacuum hot-pressing sintering technology, and the effect of VC content on their residual stress, microstructure, and mechanical properties has been studied. Residual stress in these ceramics increased with an increase of VC content. The residual compressive stress WV layer and residual tensile stress WT layer were alternately distributed in these ceramics. Adding an appropriate amount of VC could obtain a denser microstructure and finer grain. Crack deflection and crack bridging occurred in the crack propagation, and there were both transgranular fractures and intergranular fractures in these ceramics. With an increase of VC content, the relative density, flexural strength (FS), and fracture toughness (FT) of the WV layer and the Vickers hardness (VH) of the WV layer first rose and then decreased, while the VH of the WT layer kept decreasing and the FT of the WT layer had a small decrease. When the VC content was 10 wt.%, the ceramic possessed optimum comprehensive mechanical properties of an FS of 862.92 ± 11 MPa, FT of 8.52 ± 0.13 MPa m^1/2 for WV and 7.3 ± 0.13 MPa m^1/2 for WT, and a VH of 21.17 ± 0.15 GPa for WV and 20.56 ± 0.16 GPa for WT.