Mechanical properties of reactively processed W/Ta2C-based composites

The mechanical properties of reactively processed W/Ta₂C cermet composites were studied. Dense W/Ta₂C cermets with a nominal composition of 40.4 vol% W(Ta)ss, 48.9 vol% Ta₂C and 10.6 vol% Ta₂WO₈ were fabricated using a pressureless reactive processing method. Four-point bend strength, fracture toughness, elastic modulus, and microhardness were measured at room temperature. The average flexure strength was 584 MPa which is lower than for pure W; however the strength of pure Ta₂C is unknown. The fracture toughness was 8.3 MPa m^1/2 which fits a rule of mixtures between literature values for the fracture toughness of the W and Ta₂C phases. The elastic modulus was 476 GPa, and the microhardness was 13.4 GPa. Both Young's modulus and hardness were higher than values reported for other W-based cermets.