Synthesis of Dense WSi_2 and WSi_2-xvol. Percent SiC Composites by High-Frequency Induction Heated Combustion and Its Mechanical Properties

摘要

A method to synthesize the dense silicide WSi_2 and WSi_2-xvol. Percent SiC composites within two minutes in one step from W, Si and C elemental powders was investigated. Simultaneous combustion synthesis and den-sification were earned out under the combined effect of an induced current and mechanical pressure. Highly-dense WSi_2 and WSi_2-xvol. percent SiC (x = 10,20, 30) with relative density of up to 97 percent were produced under the simultaneous application of a 60 MPa pressure and the induced current on the reactant powders. The average grain size of WSi_2 in WSi_2-xvol. Percent SiC (x = 0,10,20,30) were in the region of 6.9, 6.1, 5.2, and 5.0 mu m, respectively. The respective Vickers hardness values for these materials were 1375, 1540, 1710, and 1845 kg/mm~2. From indentation crack measurements, the fracture toughness values were calculated to be 3.3, 3.8, 4.4, and 5.1 Mpa centre dot m~(1/2), respectively.