科研之友
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摘要
In this research, the mechanical properties, especially the fracture toughness (K-IC), and the microstructure of W-ZrC composites made by mixing tungsten carbide (WC) and zirconia (ZrO2) powders and applying the reaction sintering method have been investigated. For this purpose, WC and ZrO2 powders with respective volume proportions of 3:1 and 2:1 were mixed in a planetary mill and formed by a press. After pyrolysis at temperature 650 degrees C, the specimens underwent reaction sintering in vacuum at temperatures 2150 and 2250 degrees C. For measuring properties such as hardness, Young's modulus and K-IC, two different methods were used and their results were compared with each other. The XRD patterns showed the formation of W-ZrC composite following the sintering process; although slight quantities of W2C and unreacted primary compounds were also observed in each sample. The maximum values of relative density, Young's modulus and K-IC (% 98.34, 256 GPa and 6.69 MPa.root pm, respectively) were obtained in the sample made with WC and ZrO2 powders at respective volume proportions of 3:1 and sintered at temperature 2250 degrees C. Also, the maximum hardness (9.8 GPa) was obtained in the specimen made with WC: ZrO2 powders at volume proportions of 2:1 and sintered at 2250 degrees C. By observing the amount of Vickers diamond loading in each case, the maximum difference between the K-IC values obtained by a large number of equations in the Vickers Indentation Fracture (VIF) method is less than 8%, and the maximum error between the K-IC values obtained by each equation and by the Single-Edge Notch Beam (SENB) method is less than 10% in all the samples.
- 出版日期2018-2-15
