High temperature fracture of boron carbide: experiments and simple theoretical models

The mechanical properties of theoretically dense boron carbide with a grain size of about 10 μm have been investigated as a function of temperature. It was found that the fracture toughness remained constant at ∼3.7 MPa m^1/2 up to 1500 K and there was little or no decrease in strength from its room temperature value of ∼350 MPa. Both the order of magnitude and the temperature dependence of the fracture energy, calculated from the fracture toughness and elastic data, can be explained in terms of simple theoretical models.