Axial temperature gradient and stress measurements in the deformation-DIA cell using alumina pistons.

The deformation-DIA apparatus (D-DIA) coupled with synchrotron X-rays allows investigating materials elastic and plastic properties at high pressure. Most D-DIA deformation cells use alumina pistons that can also be used for measurement of the differential stress in the compression column by in situ X-ray diffraction. Here, we quantify the axial temperature (T) gradient in the D-DIA deformation cell and better constrain stress measurements in its compression column by studying an alumina specimen compressed and deformed at pressure P in the range 3.

Constitutive law and flow mechanism in diamond deformation.

Constitutive laws and crystal plasticity in diamond deformation have been the subjects of substantial interest since synthetic diamond was made in 1950's. To date, however, little is known quantitatively regarding its brittle-ductile properties and yield strength at high temperatures. Here we report, for the first time, the strain-stress constitutive relations and experimental demonstration of deformation mechanisms under confined high pressure.

In situ rheological measurements at extreme pressure and temperature using synchrotron X-ray diffraction and radiography.

Dramatic technical progress seen over the past decade now allows the plastic properties of materials to be investigated under extreme pressure and temperature conditions. Coupling of high-pressure apparatuses with synchrotron radiation significantly improves the quantification of differential stress and specimen textures from X-ray diffraction data, as well as specimen strains and strain rates by radiography. This contribution briefly reviews the recent developments in the field and describes state-of-the-art extreme-pressure deformation devices and analytical techniques available today.