Strength of tungsten triboride under pressure up to 86Â GPa from radial X-ray diffraction

The strength of tungsten triboride (WB3) was determined under nonhydrostatic compression up to 86 GPa using an angle-dispersive radial X-ray diffraction technique in a diamond-anvil cell (DAC). Analyze of diffraction data using lattice strain theory indicate that the ratio of differential stress to shear modulus (t/G) changes from 0.004 at ambient conditions to 0.078 at 86 GPa. Together with theoretical results on the high-pressure shear modulus, our results here show that WB3 under uniaxial compression can support a differential stress of 26 GPa when it starts to yield to the plastic deformation at 40 GPa. The yield strength of WB3 increases with increasing pressure, reaching a maximum value of 30 GPa at 77 GPa. By comparison, we find that the high-pressure strength of WB3 is comparable to those of c-BC2N, B6O, and γ-Si3N4.