Radial X-ray diffraction study of the static strength and equation of state of MoB2 to 85Â GPa

Investigations of strength and equation of state of α-MoB2 have been performed under nonhydrostatic compression up to 85 GPa using an angle-dispersive radial X-ray diffraction (RXD) techniques together with the lattice strain theory in a 2-fold panoramic diamond anvil cell at ambient temperature. The RXD data yields a bulk modulus and its pressure derivative as K0 = 323(6) GPa with K0′ = 4.59(27). The ratio of t/G is found to remain constant above ∼44 GPa, indicating that the α-MoB2 started to experience yield with plastic deformation at this pressure. Together with theoretical results on high-pressure shear modulus, our results here show that molybdenum diborides sample could support a differential stress of ∼18 GPa when it started to yield with plastic deformation at ∼44 GPa under uniaxial compression. A maximum differential stress, as high as ∼25 GPa can be supported by molybdenum diborides at the high pressure of ∼85 GPa.