High-density Pressureless-Sintered HfC-Based Composites

HfC-(5,10,20 vol%) MoSi2 were pressureless sintered at 1950°C in argon flux. The materials were nearly full dense (96-98%), with mean grain size 3-4 micrometers. Depending on the MoSi2 amount (5 to 20 vol%) the mechanical properties were in the following ranges: hardness 15.6-13.9 GPa, Young modulus 434-385 GPa, fracture toughness 3.6-3.4 MPa×m1/2, room temperature 4-pt flexural strength 465-383 MPa.