Rapid Consolidation of WC-ZrSiO4 Hard Materials by Spark Plasma Sintering: Microstructure, Densification, and Mechanical Properties

Abstract

Densely consolidated WC-based hard materials with 5–20 vol% ZrSiO4 was fabricated by spark plasma sintering at 1400 ℃ at a constant heating rate of 70 ℃/min−1. To achieve mechanical alloying of WC-ZrSiO4, planetary ball milling was carried out for 12 h, during which the brittle-brittle components (WC-ZrSiO4) became fragmented and their particles became refined. It was observed that certain, specific, non-isothermal sintering kinetics, such as apparent activation energy, sintering exponents, and densification strain, affected the densification behavior. The evolution of phase structure from powder to compact was found to be related the lattice distortion and micro-strain in the basal planes of WC. By examining the mechanical properties of the samples, it was that the added zircon content leads to enhanced fracture toughness (12.9 MPa m1/2) owing to the presence of WC-ZrSiO4 in the cemented carbide. In fact, the microcrack propagation of the fracture passed through zircon from a transgranular to a ductile component (fcc) where the crack tips could be absorbed. Graphic Abstract

Fabrication and performances of WC‐Co cemented carbide with a low cobalt content

“…10,11 Nonetheless, the sintering of binderless tungsten carbide is challenging. The high sintering temperature needs to be combined with advanced sintering methods such as spark plasma sintering (SPS), 12,13 hot pressing sintering (HPS) 14,15 or microwave sintering (MS) 16 to achieve full densification. The SPS and MS methods have the advantage of higher heating rates and shorter dwelling time, which can effectively inhibit the growth of grains, thus improving the properties of the sintered alloy.…”