Synthesis of W<SUB>2</SUB>C by Reactive Hot Pressing and Its Mechanical Properties

Abstract

Tungsten hemicarbide W 2 C with no or small amounts of W or WC was prepared by reaction-sintering from W and WC powders using a resistance-heated hot-pressing technique called spark plasma sintering. The product phases, density, microstructure, elastic moduli, hardness, and fracture toughness of the sintered bodies were determined. The stable region of the W 2 C phase had a narrow carbon content below 1860 C. W 2 C had a Poisson's ratio of 0.286, and its Young's modulus at zero porosity was determined to be 444 GPa from the true density and bulk density dependence. These values suggest that W 2 C has elastic deformation behavior similar to that of W.

Indentation Size Effect for the Hardness of Refractory Carbides

“…At a low test force, where the size of an indentation 22) and ZrO 2 -toughened mullite. 6) In metallic materials, specimen surfaces elastically and then plastically deform during indentation tests.…”

“…Young's modulus of the prepared refractory carbides ranged from 400 to 712 GPa. Young's modulus of the carbides has been reported in the literature as 460 GPa for B 4 C, 10,11) 223-534 GPa for Mo 2 C, 10,[12][13][14][15][16][17][18] 338-540 GPa for NbC, 10,[12][13][14][15][16][17]19) 269-486 GPa for TiC, 10,[12][13][14][15]17,18,20,21) 255-434 GPa for VC, [12][13][14][15]18,20,21) 430 GPa for W 2 C, 13,14,22) 519-707 GPa for WC, 10,12,[14][15][16]20) and 195-549 GPa for ZrC. [12][13][14][15]17,22) Poisson's ratio of ceramics at relatively low porosity is not influenced by th...…”

Synthesis of TiB<SUB>2</SUB>-TiC-Ti<SUB>3</SUB>SiC<SUB>2</SUB> Composites by Reactive Hot Pressing of B<SUB>4</SUB>C-SiC-Ti Powder Mixtures

“…According to the study of the solid-state reactions between B 4 C and Ti powders, 31) TiB 2 and TiC are substantially produced at 1000 C. In our study, temperature was measured for a graphite die. Although real sample temperature becomes higher than die temperature with increasing temperature in the resistance-heated hot-pressing system used in this study, the temperature differences is small below 1200 C, e.g., 1231 C at a die temperatures of 1200 C. 32) Points A and C are both located near 960 C. The reaction of eq. (1) accompanies a volume reduction.…”

Tribological Characteristics of Tungsten Carbide Reinforced Arc Sprayed Coatings using Different Carbide Grain Size Fractions

“…As far as XRD analysis reveals the partially dissolution of eutectic tungsten carbides and the formation of eta carbides, those metallurgical interactions might affect the mechanical response of the stressed surface. Mechanical properties such as hardness and Young's modulus of different phases of the Fe-W-C-system can be found in literature [32][33][34][38][39][40][41][42][43][44]. Relevant carbides and others are listed in the following Table 2.…”

“…Fe2W2C [34] 274.5 7.63 Fe3W3C [32][33][34] 446.1-469.7 15.6-16.8 Fe6W6C [32,34] 446.6 14.73-15.6 Fe21W2C6 [34] 437.6 14.99 Tungsten Carbides h-WC [34,39,42] 690.9-697 16-22 WC [40,44] 710 23.5 h-W2C [42] 479.6 o-W2C [42] 437.2 t-W2C [42] 427.3 W2C [40,43,44] 420-444 29.4 Others Fe [38,41] 141 W [41,43] 400-410 Fe3C [33,34,40] 306-311.04…”