ZrO_2 (3Y) toughened WC composites prepared by spark plasma sintering

摘要

WC-ZrO_2 (3Y) composites were densified by spark plasma sintering. The influence of ZrO_2 content on the densiflcation behavior, microstructure and mechanical properties of the composites were investigated. Adding ZrO_2 into WC can facilitate sintering, but will not cause rapid WC-grain-growth. After sintering, most of the tetragonal ZrO_2 remain until at room temperature, and partially transform to monoclinic structure during fracture, which exerts toughening effect. The Palmqvist cracks, rather than half-penny cracks, are observed in the high ZrO_2-content grade composites (≥6 wt.%). As the ZrO_2 content increases from 0 to 6 wt.%, the fracture toughness of the WC materials increases from ～6MP am~(1/2) to ～10.6 MPa m~(1/2) with an elevation of ～77%; while the ZrO_2 content continues to increase to 10 wt.%, the fracture toughness of the WC-ZrO_2 composites is near constant.