Microstructure and mechanical properties of ZrC-TaC_x composite fabricated by displacive compensation of porosity at 1300 °C

ZrC-TaC_x composites synthesized via Displacive Compensation of Porosity method 1300 °C using porous TaC preforms and Zr-Cu binary melts (Zr₂Cu, ZrCu and Zr₁₄Cu₅₁) are presented in this work. Effect of Zr content in the infiltration on microstructure is investigated by XRD, FE-SEM and TEM analysis. The results indicate that ZrC and platelet-like Ta₂C formed during the reactive infiltration of Zr-Cu melts into TaC preforms. The nano precipitations in TaC_x/ZrC grains and Ta atoms dissolved in ZrC suggests a probable dissolution-precipitation mechanism of the reaction between Zr-Cu melts and TaC. The ZrC-TaC_x composite exhibits a flexural strength of 142 MPa and a fracture toughness of 5.34 MPa m^1/2. The platelet-like Ta₂C phase has toughening effect by crack deflection and bridging.