Microstructure and Mechanical Properties of W-ZrC Composites Synthesized by Reactive Melt Infiltration of Zr2Cu into Porous Preforms from Partially Carburized W Powders.

W-ZrC composites with different W contents from 48 to 73 vol.% have been synthesized by reactive melt infiltration of Zr₂Cu melt into porous preforms from partially carburized W powders at 1300 °C for 1 h in vacuum. The influences of carbon content and porosity in the preforms on microstructure and mechanical properties of W-ZrC composites are investigated. Cold isostatic pressing followed by pre-sintering process is used to produce porous preforms with suitable porosities of 53.6-47% under a pressure of 100 MPa to allow sufficient penetration of Zr₂Cu melt into the preforms. Small amounts of Cu-rich phases form in the synthesized W-ZrC composites after a complete reaction of <italic>y/2x</italic>Zr₂Cu(l) + WC_{<italic>y</italic>}(s) = <italic>y/x</italic>ZrC_{<italic>x</italic>}(s) + W(s) + <italic>y/2x</italic>Cu(l). These Cu-rich phases are distributed not only at the phase boundaries of W matrix and ZrC grains, but also in the interior of ZrC_{<italic>x</italic>} grains. With decreasing W content from 73 to 48 vol.% in the W-ZrC composites, the flexural strength and fracture toughness increase from 519 to 657 MPa and from 9.1 to 10.6 MPa m^1/2, respectively. [ABSTRACT FROM AUTHOR]