The stress behavior of nanocrystalline cubic boron carbon nitride (c -BC2 N) was investigated using radial and axial x-ray diffractions in the diamond-anvil cell under nonhydrostatic compression up to ∼100 GPa. The radial x-ray diffraction (RXRD) data yield a bulk modulus K0 =276±20 GPa with a fixed pressure derivative K0′ =3.4 at ψ=54.7deg;, which corresponds to the hydrostatic compression curve. The bulk modulus obtained from axial x-ray diffraction (AXRD) gives a value of 420±11 GPa. A comparative study of the observed compression curves from radial and axial diffractions shows that the ruby-fluorescence pressure scale may reflect the maximum stress under nonhydrostatic compression. It was found that nanocrystalline c -BC2 N sample could support a maximum differential stress of ~38 GPa when it started to yield at ~66 GPa under uniaxial compression. Moreover, the aggregate elastic moduli of the nanocrystalline c -BC2 N have been determined from the RXRD data at high pressures.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Jan 5 2009|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics