The relation of the yield stress of high-pressure anvils to the pressure attained at yielding and the ultimate attainable pressure
- 1 February 1979
- journal article
- research article
- Published by AIP Publishing in Journal of Applied Physics
- Vol. 50 (2), 582-588
- https://doi.org/10.1063/1.326068
Abstract
Using a sensitive microprofilometer, the onset of yielding in the anvils of a supported opposed anvil device can readily be determined. If the pressure at which yielding occurs is measured, the yield stress of the anvil material can be obtained. This is illustrated for 3% cobalt cemented tungsten carbide. The reverse is also true and can be used as the basis for obtaining the transition pressures of a material that transforms to a conducting phase at a pressure near which yielding of the anvil material commences. This is illustrated for the gallium phosphide transition which is found to be near 18 GPa based on the commencement of yielding in boron carbide anvils. Moreover, the yield stress or Knoop hardness can be used as the basis for obtaining the ultimate attainable pressures in supported opposed anvil devices. Based on the measured yield stress of a maraging steel, and the experimental observation that the bismuth transition is near or at the ultimate attainable pressure of this steel in a supported opposed anvil device, the III–V transition is found to be near 7.7 GPa. Based on the Knoop hardness and the previously mentioned observation, this transition is found to be near 7.5 GPa. Based on the measured yield stress of a 3% cobalt cemented tungsten carbide anvil, the ultimate pressure attainable in a supported opposed anvil device is found to be about 18 GPa and in any case less than 19 GPa. Inasmuch as the gallium phosphide transition occurs near the limit of the ultimate attainable pressure with such tungsten carbide pistons, the transition pressure of gallium phosphide to a conducting phase under the stress state present there is near 18 GPa. Based on the ultimate attainable pressure in boron carbide pistons the completion of the transition of sulfur to a conducting phase is found to be less than 33 GPa. The yielding of supported opposed diamond anvils with dislocation densities of ∼5×104/cm2 or more is expected to be in the neighborhood of 50 GPa. The onset of this yielding could be used as the basis for determining approximately the transition pressure of silicon carbide to a conducting phase at an estimated value of 64 GPa.This publication has 14 references indexed in Scilit:
- Pressure transition of AlP to a conductive phaseJournal of Applied Physics, 1976
- Yield stress of cemented tungsten carbideJournal of Applied Physics, 1975
- High pressures with supported opposed steel anvilsReview of Scientific Instruments, 1975
- Pressure dependence of elastic moduli of tungsten carbide cermetJournal of Applied Physics, 1973
- Quantum Dielectric Theory of Electronegativity in Covalent Systems. III. Pressure-Temperature Phase Diagrams, Heats of Mixing, and Distribution CoefficientsPhysical Review B, 1973
- High-Pressure Calibration: A Critical ReviewJournal of Physical and Chemical Reference Data, 1972
- Dynamic Yield Strengths of B4C, BeO, and Al2O3 CeramicsJournal of Applied Physics, 1971
- Crushing Strength of Cemented Tungsten Carbide PistonsReview of Scientific Instruments, 1967
- Determination of the Pressure of the Barium I-II Transition with Single-Stage Piston-Cylinder ApparatusJournal of Applied Physics, 1967
- Design Variables for a High Pressure Cell with Supported Taper PistonsReview of Scientific Instruments, 1965