The deformation-DIA: A new apparatus for high temperature triaxial deformation to pressures up to 15 GPa

A new deformation apparatus has been developed, based on the widely used cubic-anvil apparatus known as the DIA. Two differential rams, introduced in the upper and lower guide blocks, allow independent control of the differential strain and stress field under high confining pressure. Testing experiments with synchrotron x rays have demonstrated that this deformation DIA (D-DIA) is capable of generating up to 30% axial strain on a 1 - 2 mm long sample under confining pressures up to 15 GPa at simultaneous high temperatures. Various compressional strain rates from 10(-3) to about 5x10(-6) s(-1) have been achieved. Extensional experiments have also been carried out successfully. Strains are measured by x-ray imaging of the sample which has a length measurement precision of similar to0.1 mum; pressures are monitored using standard materials with well established equations of state. X-ray transparent anvils made of sintered polycrystalline cubic boron nitride have been successfully tested, with a two-dimensional x-ray charge coupled device detector. Distortions in the diffraction lines due to differential stress can be measured with a precision of about 20 MPa. (C) 2003 American Institute of Physics.