Microstructural evolution and development of mechanical properties of spark plasma sintered WC–Co cemented carbides for machine parts and engineering tools

• Published in: Archives of Civil and Mechanical Engineering 2019-03, Vol.19 (1), p.215-223
• Main Authors: Garbiec, D., Siwak, P.
• Format: Article
• Language: English
• Subjects: Carbide tools; Carbon; Cemented carbides; Chromium carbide; Civil Engineering; Compacting; Decarburization; Engineering; Fracture toughness; Grain growth; Hardness; Inhibitors; Mechanical Engineering; Mechanical properties; Microstructure; Niobium carbide; Original Research Article; Plasma sintering; Spark plasma sintering; Structural Materials; Tungsten carbide
• ISSN: 1644-9665; 2083-3318
• DOI: 10.1016/j.acme.2018.10.004

WC–Co, WC–Co–Cr3C2 and WC–Co–TaC–NbC cemented carbides were spark plasma sintered and the microstructure and main mechanical properties of the obtained specimens were investigated. A series of WC–6Co cemented carbides was heated to the sintering temperature of 1400°C at 200 and 400°C/min at compacting pressures of 50 and 60MPa. It was shown that the specimens spark plasma sintered at 400°C/min and at 60MPa possess the best mechanical properties. These parameters were applied for sintering WC–6Co cemented carbides with addition of grain growth inhibitors such as Cr3C2 and TaC–NbC. The influence of the grain growth inhibitors content was studied. The X-ray diffraction test results show that decarburization of the WC phase occurred and carbon deficient W2C and η (Co3W3C, Co6W6C) phases were formed during spark plasma sintering, wherein an increase in compacting pressure from 50 to 60MPa results in a diminution in the carbon diffusion processes. The mechanical properties of the cemented carbides were defined. The best ratio of hardness and fracture toughness was obtained for WC–6Co–1Cr3C2: hardness was 1808±19 HV30 and fracture toughness was 10.17±0.27MPam1/2.