Deformation T-Cup: A new multi-anvil apparatus for controlled strain-rate deformation experiments at pressures above 18 GPa

Abstract

A new multi-anvil deformation apparatus, based on the widely used 6-8 split-cylinder, geometry, has been developed which is capable of deformation experiments at pressures in excess of 18 GPa at room temperature. In 6-8 (Kawai-type) devices eight cubic anvils are used to compress the sample assembly. In our new apparatus two of the eight cubes which sit along the split-cylinder axis have been replaced by hexagonal cross section anvils. Combining these anvils hexagonal-anvils with secondary differential actuators incorporated into the load frame, for the first time, enables the 6-8 multi-anvil apparatus to be used for controlled strain-rate deformation experiments to high strains. Testing of the design, both with and without synchrotron-X-rays, has demonstrated the Deformation T-Cup (DT-Cup) is capable of deforming 1–2 mm long samples to over 55% strain at high temperatures and pressures. To date the apparatus has been calibrated to, and deformed at, 18.8 GPa and deformation experiments performed in conjunction with synchrotron X-rays at confining pressures up to 10 GPa at 800 °C .

An Experimental Investigation of the Relative Strength of the Silica Polymorphs Quartz, Coesite, and Stishovite

“…The results reported here are further analyses of three experiments, initially reported by Hunt et al (), that were performed during commissioning of the DT‐Cup on the side‐station beamline X17B2ss at the NSLS. The DT‐Cup is a modified split‐cylinder six to eight multianvil capable of controlled strain rate deformation experiments (Hunt et al, ; Hunt & Dobson, ). The 〈111〉 axes of the inner cubic anvils are aligned with the compression direction of the loading frame.…”

Dislocations and Plastic Deformation in MgO Crystals: A Review

“…The D-DIA is designed for deformation at constant pressure, both compressional and extensional, at strain rates between 10 −3 and 10 −7 /s and, currently, up to 18 GPa and 1900 K [238]. The DT-Cup allows for controlled deformation in axial geometry with experiments at about 20 GPa at 300 K and 10 GPa at 1100 K [237]. Finally, the RDA allows a large rotational shear deformation of the sample up to pressures and temperatures over 27 GPa at 2150 K [239].…”

“…The deformation-DIA (D-DIA) [235], Rotational Drickamer Apparatus (RDA) [236], and newly developed Deformation T-Cup (DT-Cup) [237] are the three main large volume presses (LVP) used for high pressure plasticity studies. All allow the controlled deformation of millimeter size samples.…”

Note: Modified anvil design for improved reliability in DT-Cup experiments

“…The deformation 6-8 multi-anvil (DT-Cup), as reported by Hunt et al, 14 is capable of performing deformation experiments at pressures in excess of 18 GPa but with a subsequently discovered, unacceptably high failure rate. These failures were primarily due to vertical cracking of the unsupported hexagonal anvils.…”

“…14 In a hydrostatic 6-8 multi-anvil, the sample is contained within an octahedral pressure medium and compressed by 8 secondstage anvils each of which is a corner-truncated cube. The a) simon.hunt@ucl.ac.uk anvils are arranged such that each corner truncation acts on a face of the octahedral pressure medium.…”