In situ Reaction Synthesis and Mechanical Properties of TaC-TaSi2 Composites

TaC-TaSi2 composites were fabricated at 1700 degrees C by an in situ reaction/hot pressing method using Ta, Si, and graphite as initial materials. TaSi2 content was 0-100 vol%. The microstructure and mechanical properties of the composites were investigated. It was found that the relative densities of composites were above 97.5% when the volume content of TaSi2 was above 10%. The TaC/10 vol% TaSi2 composite presented the highest flexural strength of 376 MPa. When the TaSi2 content was 30-50 vol%, the composites showed the highest fracture toughness of about 4.3MP . am(1/2). In addition, the composites could retain high Young's modulus up to at least 15251 degrees C.