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Rotational Diamond Anvil Cell Laboratory at ISU

Rotational Diamond Anvil Cell Laboratory at ISU. Acknowledgments: -Army Research Office (W911NF-17-1-0225 & DURIP W911NF-17-1-0196) Dr. David Stepp. PI: Dist. Prof. Valery I. Levitas Laboratory Manager: Dr. Krishan Kumar Pandey, post doc. Department of Aerospace Engineering

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Rotational Diamond Anvil Cell Laboratory at ISU

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  1. Rotational Diamond Anvil Cell Laboratory at ISU Acknowledgments: -Army Research Office (W911NF-17-1-0225 & DURIP W911NF-17-1-0196) Dr. David Stepp PI: Dist. Prof. Valery I. Levitas Laboratory Manager: Dr. Krishan Kumar Pandey, post doc Department of Aerospace Engineering Iowa State University, Ames, IA

  2. Rotational Diamond Anvil Cell (RDAC) • New automated rotational cell with diamond anvils for in-situ x-ray diffraction and Raman scattering studies, with a pressure range up to 100 GPa and unlimited torsion, has been designed, developed, and manufactured. Pressure distribution is determined using luminescence of distributed ruby particles. Displacement of ruby particles is utilized to determine displacement field in a sample and gasket. • This cell will be used to perform experimental investigations on materials under controlled stress environment utilizing plastic strain tensors and plastic strain-induced defect structure as new thermodynamic and kinetic parameters to induce phase transformations (PTs) and to utilize this information for developing material synthesis approaches under such conditions. Laser focusing and signal collection Objective 1 2 3 4 5 6 7 8 Rotational diamond anvil cell (RDAC) 1-limb; 2-gear; 3-flange; 4-connector; 5-frame; 6-screw for alignment of inclination; 7- screw for alignment along axis rotation; 8-bottom

  3. Rotational Diamond Anvil Cell (RDAC) Design Scheme of a RDAC: movable piston (1), case (2), bottom (3), screw (4), hemispheric upper support (5), tooth gear (6), limb (7), flange (8), upper support (9), bottom support (10), hemispheric bottom support (11), hemispheric support (12), textolite plate (13), screw (14), steel plate (15), screws (16–20), movable diamond anvil (21), unmovable diamond anvil (22). Scheme of the diamond cell: 1—diamond anvil, 2—culet, 3—gasket, 4—sample. Ref.: N. B. Novikov, L. K. Shvedov, Yu. N. Krivosheya and V. I. Levitas; Journal of Superhard Materials, 2015, Vol. 37, No. 1, pp. 1–7.

  4. Rotational Diamond Anvil Cell (RDAC) Design Scheme of a RDAC with the loading device: RDAC (1), levers (2), disk springs (3), axis (4), switching device (5), case (6), reducer (7). Ref.: N. B. Novikov, L. K. Shvedov, Yu. N. Krivosheya and V. I. Levitas; Journal of Superhard Materials, 2015, Vol. 37, No. 1, pp. 1–7.

  5. Rotational Diamond Anvil Cell Automation Software Screenshot of RDAC controller software Laser focusing and signal collection Objective The loading and shear conditions on sample in RDAC is controlled using LABVIEW GUI based software. Using this software, one can easily switch between load and shear mode, apply desired load and shear and also monitor sample thickness using capacitance-measurement based system incorporated in RDAC.

  6. Rotational Diamond Anvil Cell Laboratory Micro-confocal Raman system • The Micro-confocal Raman system has been designed, assembled and aligned. • This system is equipped with 532 nm, 300 mW diode pumped solid state laser (as excitation source) and Andor 500i spectrometer with AndoriDUS CCD detector for recording Raman spectra (both Stokes and anti-Stokes) starting from 5 cm-1 onwards with a resolution of ~ 2-3 cm-1 . • This system is capable of recording Raman signal from sample size as small as 1 micron and with 2 axis motorized stages at sample position, it can be used for 2D Raman imaging with a resolution of 1 micron. • This system is also equipped with magnified viewing arrangement with 10X magnification to precisely align sample position with respect to excitation laser spot. Confocal Raman signal collection optics Spectrometer RDAC system Motorized actuators for sample alignment Laser spot on calibration scale as viewed from viewing arrangement in Raman system

  7. Rotational Diamond Anvil Cell Laboratory Micro-confocal Raman system Laser focusing and signal collection Objective Rotation diamond anvil cell system camera laser LED illuminator Confocal collection optics manual X stage for bringing sample to focal plane and motorized YZ stage for sample alignment with respect to laser and 2D Raman imaging Inside view of confocal collection optics

  8. Rotational Diamond Anvil Cell Laboratory Optical layout of Micro-confocal Raman system Laser focusing and signal collection Objective

  9. Rotational Diamond Anvil Cell Laboratory Other facilities at RDAC lab Electrical discharge machine Rolling mill Mechanical micro-drill machine Stereo-zoom microscope

  10. Rotational Diamond Anvil Cell Laboratory Screenshot of Raman mapping software A python GUI based software has been developed to control sample positioning stage and record Raman spectra from desired position Laser focusing and signal collection Objective This software has built in 1D and 2D Raman /ruby fluorescence mapping macros, useful for estimating pressure and displacement fields at sample loaded in RDAC.

  11. Displacement field measurements in RDAC using ruby fluorescence imaging Ruby fluorescence images Results from digital image correlation analysis Before shear After shear Overlapping ruby fluorescence images where magenta color represents before shear and green color represents after shear image.

  12. Pressure field measurements in RDAC using Raman peak shift of diamond anvil Pressure (GPa) Radial profiles of pressure distribution at various load conditions in Cu gasket. 2D map of pressure field in tungsten gasket at 105 kgfload. Each pixel corresponds to 10 micron step.

  13. Pressure and phase field measurements in RDAC using micro- X-ray diffraction measurements at Advanced photon source beamlines Phase fraction weighted pressure map of Zr at same load-shear condition Azimuthally averaged radial profiles of pressure and phase fields of Zr at same load-shear condition 2D map of volume per atom in  and  phases of Zr after    transition

  14. Kinetics of strain induced    transition in Zr Kinetic equation: k : kinetic parameter : minimum pressure for direct strain-induced phase transition : phase transition pressure under hydrostatic loading : 5.9 GPa From fitting: k : 26.4647 : 1.22 GPa

  15. Rotational Diamond Anvil Cell Laboratory Location: Room no. 0328B, Howe Hall 537 Bissell Road Ames, IA 50011

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