X-ray diffraction study of the static strength of tungsten to 69 GPa

The strength of tungsten was determined under static high pressures to 69 GPa using x-ray diffraction techniques in a diamond anvil cell. Analysis of x-ray diffraction peak broadening and measurement of peak shifts associated with lattice strains are two different methods for strength determination of materials under large nonhydrostatic compressions. Here these methods are directly compared under uniaxial compression in a diamond anvil cell. Our results demonstrate the consistency of the two approaches, and show that the yield strength of tungsten increases with compression, reaching a value of 5.3 GPa at the highest pressure. The obtained yield strength of tungsten is also compared with previous experimental data involving shock wave and static compression measurements, and with theoretical predictions. The high-pressure strength of tungsten is comparable to that of other dense metals such as Re and Mo, and ratio of yield strength to shear modulus is about 0.02 for all these materials between 20 and 70 GPa. The static strength of tungsten is much greater than values observed for W under shock loading but is very similar to values observed under quasi-isentropic loading.