Synthesis of dense WSi2 and WSi2-xvol.%SiC composites by high-frequency induction heated combustion and its mechanical properties

Abstract

A method to synthesize the dense silicide WSi2 and WSi2-xvol.%SiC composites within two minutes in one step from W, Si and C elemental powders was investigated. Simultaneous combustion synthesis and densification were carried out under the combined effect of an induced current and mechanical pressure. Highly dense WSi2 and WSi2-xvol.%SiC (x = 10, 20, 3 0) with relative density of up to 97 % were produced under the simultaneous application of a 60 MPa pressure and the induced current on the reactant powders. The average grain size of WSi2 in WSi2-xvol-%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.m(1/2), respectively.