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At least 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Mg(InTe2)2 by Materials Project

Mg(InTe2)2 crystallizes in the tetragonal I-4 space group. The structure is three-dimensional. Mg2+ is bonded to four equivalent Te2- atoms to form MgTe4 tetrahedra that share corners with eight InTe4 tetrahedra. All Mg–Te bond lengths are 2.84 Å. There are two inequivalent In3+ sites. In the first In3+ site, In3+ is bonded to four equivalent Te2- atoms to form InTe4 tetrahedra that share corners with four equivalent MgTe4 tetrahedra and corners with four equivalent InTe4 tetrahedra. All In–Te bond lengths are 2.86 Å. In the second In3+ site, In3+ is bonded to four equivalent Te2- atoms to form InTe4 tetrahedra that share corners with four equivalent MgTe4 tetrahedra and corners with four equivalent InTe4 tetrahedra. All In–Te bond lengths are 2.85 Å. Te2- is bonded in a distorted trigonal non-coplanar geometry to one Mg2+ and two In3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(InSe2)2 by Materials Project

Mg(InSe2)2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Mg2+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of Mg–Se bond distances ranging from 2.74–3.25 Å. There are two inequivalent In3+ sites. In the first In3+ site, In3+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing InSe6 octahedra. The corner-sharing octahedra tilt angles range from 49–62°. There are a spread of In–Se bond distances ranging from 2.71–2.92 Å. In the second In3+ site, In3+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing InSe6 octahedra. The corner-sharing octahedra tilt angles range from 49–62°. There are a spread of In–Se bond distances ranging from 2.76–2.86 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Mg2+ and two equivalent In3+ atoms to form a mixture of edge and corner-sharing SeMg3In2 square pyramids. In the second Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to four In3+ atoms. In the third Se2- site, Se2- is bonded in a 5-coordinate geometry to two equivalent Mg2+ and three In3+ atoms. In the fourth Se2- site, Se2- is bonded to two equivalent Mg2+ and three In3+ atoms to form SeMg2In3 square pyramids that share corners with two equivalent SeMg3In2 square pyramids and edges with five SeMg2In3 square pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(BH4)2 by Materials Project

Mg(BH4)2 crystallizes in the cubic Ia-3d space group. The structure is three-dimensional. Mg2+ is bonded to eight H+0.50+ atoms to form distorted MgH8 hexagonal bipyramids that share edges with four equivalent BH4 tetrahedra. There are four shorter (2.05 Å) and four longer (2.08 Å) Mg–H bond lengths. B3- is bonded to four H+0.50+ atoms to form BH4 tetrahedra that share edges with two equivalent MgH8 hexagonal bipyramids. There is two shorter (1.22 Å) and two longer (1.23 Å) B–H bond length. There are two inequivalent H+0.50+ sites. In the first H+0.50+ site, H+0.50+ is bonded in an L-shaped geometry to one Mg2+ and one B3- atom. In the second H+0.50+ site, H+0.50+ is bonded in an L-shaped geometry to one Mg2+ and one B3- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(CuN)3 by Materials Project

Mg(CuN)3 crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Mg2+ is bonded to six equivalent N3- atoms to form corner-sharing MgN6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Mg–N bond lengths are 2.07 Å. Cu+2.33+ is bonded in a square co-planar geometry to four equivalent N3- atoms. All Cu–N bond lengths are 2.07 Å. N3- is bonded to two equivalent Mg2+ and four equivalent Cu+2.33+ atoms to form a mixture of corner and edge-sharing NMg2Cu4 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(N3Cl)2 by Materials Project

Mg(N3Cl)2 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Mg2+ is bonded to six equivalent N atoms to form MgN6 octahedra that share faces with eight equivalent ClN12 cuboctahedra. All Mg–N bond lengths are 2.20 Å. N is bonded in a single-bond geometry to one Mg2+ and four equivalent Cl1- atoms. All N–Cl bond lengths are 2.93 Å. Cl1- is bonded to twelve equivalent N atoms to form ClN12 cuboctahedra that share corners with twelve equivalent ClN12 cuboctahedra, faces with six equivalent ClN12 cuboctahedra, and faces with four equivalent MgN6 octahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(ScS2)2 by Materials Project

Mg(ScS2)2 crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Mg2+ is bonded in a 4-coordinate geometry to eight equivalent S2- atoms. There are four shorter (2.53 Å) and four longer (3.11 Å) Mg–S bond lengths. Sc3+ is bonded in a 8-coordinate geometry to eight equivalent S2- atoms. There are a spread of Sc–S bond distances ranging from 2.56–3.07 Å. S2- is bonded in a 6-coordinate geometry to two equivalent Mg2+ and four equivalent Sc3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(InS2)2 by Materials Project

MgIn2S4 crystallizes in the triclinic P-1 space group. The structure is two-dimensional and consists of one MgIn2S4 sheet oriented in the (0, 0, 1) direction. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four S2- atoms to form MgS4 tetrahedra that share a cornercorner with one MgS6 octahedra, corners with two equivalent InS6 octahedra, and corners with six InS4 tetrahedra. The corner-sharing octahedra tilt angles range from 58–59°. There are a spread of Mg–S bond distances ranging from 2.45–2.48 Å. In the second Mg2+ site, Mg2+ is bonded to six S2- atoms to form MgS6 octahedra that share a cornercorner with one MgS4 tetrahedra, corners with five InS4 tetrahedra, edges with two equivalent MgS6 octahedra, and edges with four equivalent InS6 octahedra. There are a spread of Mg–S bond distances ranging from 2.61–2.64 Å. There are four inequivalent In3+ sites. In the first In3+ site, In3+ is bonded to four S2- atoms to form InS4 tetrahedra that share a cornercorner with one InS6 octahedra, corners with two equivalent MgS6 octahedra, corners with two equivalent MgS4 tetrahedra, and corners with four InS4 tetrahedra. The corner-sharing octahedra tilt angles range from 58–61°. There are a spread of In–S bond distances ranging from 2.47–2.53 Å. In the second In3+ site, In3+ is bonded to six S2- atoms to form InS6 octahedra that share corners with two equivalent MgS4 tetrahedra, corners with four InS4 tetrahedra, edges with two equivalent InS6 octahedra, and edges with four equivalent MgS6 octahedra. There are a spread of In–S bond distances ranging from 2.62–2.70 Å. In the third In3+ site, In3+ is bonded to four S2- atoms to form InS4 tetrahedra that share a cornercorner with one InS6 octahedra, corners with two equivalent MgS6 octahedra, corners with two equivalent MgS4 tetrahedra, and corners with four InS4 tetrahedra. The corner-sharing octahedra tilt angles range from 58–61°. There are a spread of In–S bond distances ranging from 2.47–2.54 Å. In the fourth In3+ site, In3+ is bonded to four S2- atoms to form InS4 tetrahedra that share a cornercorner with one MgS6 octahedra, corners with two equivalent InS6 octahedra, corners with two equivalent MgS4 tetrahedra, and corners with four InS4 tetrahedra. The corner-sharing octahedra tilt angles range from 58–61°. There are three shorter (2.49 Å) and one longer (2.53 Å) In–S bond lengths. There are eight inequivalent S2- sites. In the first S2- site, S2- is bonded to two equivalent Mg2+ and two In3+ atoms to form distorted SMg2In2 trigonal pyramids that share corners with seven SMgIn3 tetrahedra, corners with two equivalent SMg2In2 trigonal pyramids, an edgeedge with one SMg2In2 tetrahedra, and edges with two SMg2In2 trigonal pyramids. In the second S2- site, S2- is bonded to two Mg2+ and two equivalent In3+ atoms to form distorted SMg2In2 trigonal pyramids that share corners with seven SMgIn3 tetrahedra, corners with two equivalent SMg2In2 trigonal pyramids, an edgeedge with one SMgIn3 tetrahedra, and edges with two SMg2In2 trigonal pyramids. In the third S2- site, S2- is bonded in a trigonal non-coplanar geometry to one Mg2+ and two In3+ atoms. In the fourth S2- site, S2- is bonded in a trigonal non-coplanar geometry to three In3+ atoms. In the fifth S2- site, S2- is bonded in a trigonal non-coplanar geometry to one Mg2+ and two In3+ atoms. In the sixth S2- site, S2- is bonded in a trigonal non-coplanar geometry to one Mg2+ and two In3+ atoms. In the seventh S2- site, S2- is bonded to one Mg2+ and three In3+ atoms to form distorted SMgIn3 tetrahedra that share corners with two equivalent SMg2In2 tetrahedra, corners with seven SMg2In2 trigonal pyramids, edges with two SMgIn3 tetrahedra, and an edgeedge with one SMg2In2 trigonal pyramid. In the eighth S2- site, S2- is bonded to two equivalent Mg2+ and two In3+ atoms to form distorted SMg2In2 tetrahedra that share corners with two equivalent SMgIn3 tetrahedra, corners with seven SMg2In2 trigonal pyramids, edges with two SMgIn3 tetrahedra, and an edgeedge with one SMg2In2 trigonal pyramid.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(ScSe2)2 by Materials Project

Mg(ScSe2)2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Mg2+ is bonded to seven Se2- atoms to form distorted MgSe7 pentagonal bipyramids that share corners with eight ScSe6 octahedra, edges with five ScSe6 octahedra, edges with two equivalent MgSe7 pentagonal bipyramids, and faces with two equivalent MgSe7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 12–64°. There are a spread of Mg–Se bond distances ranging from 2.76–3.09 Å. There are two inequivalent Sc3+ sites. In the first Sc3+ site, Sc3+ is bonded to six Se2- atoms to form ScSe6 octahedra that share corners with three equivalent ScSe6 octahedra, corners with four equivalent MgSe7 pentagonal bipyramids, edges with six ScSe6 octahedra, and an edgeedge with one MgSe7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 51–59°. There are a spread of Sc–Se bond distances ranging from 2.68–2.82 Å. In the second Sc3+ site, Sc3+ is bonded to six Se2- atoms to form ScSe6 octahedra that share corners with three equivalent ScSe6 octahedra, corners with four equivalent MgSe7 pentagonal bipyramids, edges with four ScSe6 octahedra, and edges with four equivalent MgSe7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 51–59°. There are a spread of Sc–Se bond distances ranging from 2.69–2.75 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Mg2+ and two equivalent Sc3+ atoms to form a mixture of edge and corner-sharing SeMg3Sc2 square pyramids. In the second Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to four Sc3+ atoms. In the third Se2- site, Se2- is bonded to two equivalent Mg2+ and three Sc3+ atoms to form a mixture of distorted edge and corner-sharing SeMg2Sc3 trigonal bipyramids. In the fourth Se2- site, Se2- is bonded to two equivalent Mg2+ and three Sc3+ atoms to form SeMg2Sc3 square pyramids that share corners with two equivalent SeMg3Sc2 square pyramids, corners with two equivalent SeMg2Sc3 trigonal bipyramids, edges with five SeMg2Sc3 square pyramids, and edges with three equivalent SeMg2Sc3 trigonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(ZnSb)2 by Materials Project

Mg(ZnSb)2 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Mg2+ is bonded to six equivalent Sb3- atoms to form MgSb6 octahedra that share corners with twelve equivalent ZnSb4 tetrahedra, edges with six equivalent MgSb6 octahedra, and edges with six equivalent ZnSb4 tetrahedra. All Mg–Sb bond lengths are 3.05 Å. Zn2+ is bonded to four equivalent Sb3- atoms to form ZnSb4 tetrahedra that share corners with six equivalent MgSb6 octahedra, corners with six equivalent ZnSb4 tetrahedra, edges with three equivalent MgSb6 octahedra, and edges with three equivalent ZnSb4 tetrahedra. The corner-sharing octahedra tilt angles range from 11–56°. There are three shorter (2.74 Å) and one longer (2.80 Å) Zn–Sb bond lengths. Sb3- is bonded to three equivalent Mg2+ and four equivalent Zn2+ atoms to form a mixture of distorted edge and corner-sharing SbMg3Zn4 pentagonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(ScS2)2 by Materials Project

Mg(ScS2)2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Mg2+ is bonded to seven S2- atoms to form distorted MgS7 pentagonal bipyramids that share corners with eight ScS6 octahedra, edges with five ScS6 octahedra, edges with two equivalent MgS7 pentagonal bipyramids, and faces with two equivalent MgS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 11–65°. There are a spread of Mg–S bond distances ranging from 2.62–2.99 Å. There are two inequivalent Sc3+ sites. In the first Sc3+ site, Sc3+ is bonded to six S2- atoms to form ScS6 octahedra that share corners with three equivalent ScS6 octahedra, corners with four equivalent MgS7 pentagonal bipyramids, edges with six ScS6 octahedra, and an edgeedge with one MgS7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 52–59°. There are a spread of Sc–S bond distances ranging from 2.55–2.66 Å. In the second Sc3+ site, Sc3+ is bonded to six S2- atoms to form ScS6 octahedra that share corners with three equivalent ScS6 octahedra, corners with four equivalent MgS7 pentagonal bipyramids, edges with four ScS6 octahedra, and edges with four equivalent MgS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 52–59°. There are a spread of Sc–S bond distances ranging from 2.56–2.64 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded to three equivalent Mg2+ and two equivalent Sc3+ atoms to form a mixture of corner and edge-sharing SMg3Sc2 square pyramids. In the second S2- site, S2- is bonded in a rectangular see-saw-like geometry to four Sc3+ atoms. In the third S2- site, S2- is bonded in a 5-coordinate geometry to two equivalent Mg2+ and three Sc3+ atoms. In the fourth S2- site, S2- is bonded to two equivalent Mg2+ and three Sc3+ atoms to form SMg2Sc3 square pyramids that share corners with two equivalent SMg3Sc2 square pyramids and edges with five SMg2Sc3 square pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(InSe2)2 by Materials Project

Mg(InSe2)2 crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Mg2+ is bonded to four equivalent Se2- atoms to form distorted MgSe4 trigonal pyramids that share corners with eight equivalent InSe4 tetrahedra. All Mg–Se bond lengths are 2.62 Å. In3+ is bonded to four equivalent Se2- atoms to form distorted InSe4 tetrahedra that share corners with four equivalent InSe4 tetrahedra and corners with four equivalent MgSe4 trigonal pyramids. All In–Se bond lengths are 2.64 Å. Se2- is bonded in a trigonal non-coplanar geometry to one Mg2+ and two equivalent In3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg(AlH4)2 by Materials Project

Mg(AlH4)2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. Mg2+ is bonded to six H1- atoms to form MgH6 octahedra that share corners with six AlH5 trigonal bipyramids. There are a spread of Mg–H bond distances ranging from 1.87–1.98 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to five H1- atoms to form distorted AlH5 trigonal bipyramids that share corners with three equivalent MgH6 octahedra and an edgeedge with one AlH5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 44–47°. There are a spread of Al–H bond distances ranging from 1.63–2.05 Å. In the second Al3+ site, Al3+ is bonded to five H1- atoms to form distorted AlH5 trigonal bipyramids that share corners with three equivalent MgH6 octahedra and an edgeedge with one AlH5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 45–48°. There are a spread of Al–H bond distances ranging from 1.63–2.04 Å. There are eight inequivalent H1- sites. In the first H1- site, H1- is bonded in a bent 150 degrees geometry to one Mg2+ and one Al3+ atom. In the second H1- site, H1- is bonded in a distorted bent 120 degrees geometry to one Mg2+ and one Al3+ atom. In the third H1- site, H1- is bonded in a bent 120 degrees geometry to one Mg2+ and one Al3+ atom. In the fourth H1- site, H1- is bonded in a water-like geometry to two Al3+ atoms. In the fifth H1- site, H1- is bonded in a water-like geometry to two Al3+ atoms. In the sixth H1- site, H1- is bonded in a bent 120 degrees geometry to one Mg2+ and one Al3+ atom. In the seventh H1- site, H1- is bonded in a distorted bent 120 degrees geometry to one Mg2+ and one Al3+ atom. In the eighth H1- site, H1- is bonded in a distorted bent 150 degrees geometry to one Mg2+ and one Al3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Reversible (De)Intercalation of Hydrated Zn 2+ in Mg 2+ -Stabilized V 2 O 5 Nanobelts with High Areal Capacity

The rechargeable aqueous zinc ion battery (ZIB) is regarded as one of the most promising candidates for large-scale energy storage applications due to its low-cost and eco-friendly properties. However, the development of a suitable cathode operating with high areal capacity and uncovering the relevant reaction mechanisms remain challenging. Herein, the application of Mg 0.26 V 2 O 5 ∙0.73H 2 O (MVO) nanobelts as a ZIB cathode is demonstrated. In situ FT-IR reveals the shift of OH stretching from 3350 cm -1 to 3200 cm -1 , corresponding to the hydration shell of Zn 2+ , while in situ Raman suggests the interlayer charges creening effect, which would boost the intercalation of hydrated Zn 2+ . Density function theory reveals that the hydrated Zn 2+ can lower the Coulombic repulsion at the electrode-electrolyte interface and circumvents the desolvation penalty of hydrated Zn 2+ during the (de)intercalation process. Additionally, excellent structure stability and large interlayer spacing guarantee the highly reversible (de)intercalation of hydrated Zn 2+ . Therefore, the MVO nanobelts exhibit a high areal capacity of 2.12 mAh cm -2 at 0.05 A g -1 , outstanding cycling stability of 2500 cycles at 10 A g -1 with a mass loading of 5 mg cm -2 . Finally, it is believed that the use of hydrated intercalation charge carriers will boost further studies in other multivalent rechargeable batteries.

25 ENERGY STORAGE↗
DOE OSTI2025

Role of Mg:Al ratio and Pt promotion on mitigating the deactivation of Ni-based methane steam reforming catalysts

Ni-based catalysts for CH 4 steam reforming require fine-tuning to withstand deactivation under dynamic operation conditions relevant to emerging H 2 -driven technologies. This study investigates the impact of the Mg:Al ratio and Pt presence in catalyst composition on the activity and stability of industrially relevant Ni-based mono- and bimetallic catalysts during simulated daily start-up and shut-down cycles in various gas atmospheres. The evolution of the catalyst structure during extensive testing procedures was investigated in detail by complementary electron microscopy, in situ/operando XAS and XRD. The results obtained revealed that catalyst deactivation is promoted at high Mg:Al ratios and especially affects the monometallic catalysts. By converting CH 4 at lower temperatures, Pt regulates the extent of Ni oxidation and its incorporation into MgO lattice. Further prevention of catalyst deactivation was achieved by optimizing the reactor shut-down procedure to minimize the simultaneous exposure to high temperatures and H 2 O vapors. By flushing the reactor with N 2 only around the reaction extinction temperature, a fraction of Ni species is maintained in metallic state, which is beneficial for the long-term activity and reaction operation economy.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Limiting velocities and transonic dislocations in Mg

To accurately predict the mechanical response of materials, especially at high strain rates, it is important to account for dislocation velocities in these regimes. Under these extreme conditions, it has been hypothesized that dislocations can move faster than the speed of sound. However, the presence of such dislocations remains elusive due to challenges associated with measuring these experimentally. In this work, molecular dynamics simulations were used to investigate the dislocation velocities for the basal edge, basal screw, prismatic edge, and prismatic screw dislocations in Mg in the sub-, trans-, and supersonic regimes. Also, our results show that only prismatic edge dislocations achieve supersonic velocities. Furthermore, this work demonstrates that the discrepancy between the theoretical limiting velocity and the MD results for Mg is due to its sensitivity to large hydrostatic stress around the dislocation core, which was not the case for fcc metals such as Cu.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Quantification of grain boundary effects on the geometrically necessary dislocation density evolution and strain hardening of polycrystalline Mg 4Al using in situ tensile testing in scanning electron microscope and HR-EBSD

In situ tensile testing in a scanning electron microscope (SEM) in conjunction with high-resolution electron backscatter diffraction (HR-EBSD) under load was used to characterize the evolution of geometrically necessary dislocation (GND) densities at individual grain boundaries as a function of applied strain in a polycrystalline Mg—4Al alloy. The increase in GND density was investigated at plastic strains of 0 %, 0.6 %, 2.2 %, 3.3 % from the area including 76 grains and correlated with (i) geometric compatibility between slip systems across grain boundaries, and (ii) plastic incompatibility. We develop expressions for the grain boundary GND density evolution as a function of plastic strain and plastic incompatibility, from which uniaxial tensile stress-strain response of polycrystalline Mg—4Al are computed and compared with experimental measurement. The findings in this study contribute to understanding the mechanisms governing the strain hardening response of single-phase polycrystalline alloys and more reliable prediction of mechanical behaviors in diverse microstructures.

Geometrically necessary dislocations↗
DOE OSTI2022

Correlating dislocation structures to basal and prismatic slip bands near grain boundaries in tensile-tested Mg–4Al using a multiscale electron microscopy approach

Dislocation structures where basal and prismatic slip bands meet grain boundaries in tensile-tested Mg with 4 wt% Al (Mg–4Al) were studied using a multiscale electron microscopy approach to explore the assumptions made for the dislocation pileup theory: a) slip bands consist of dislocation arrays piling up near grain boundaries, and b) stress concentration in the adjacent grain is solely caused by dislocation pileup. After post-testing electron backscatter diffraction (EBSD) scans, focused-ion-beam (FIB) lift-out specimens were prepared from regions of interest so that the specimen plane is parallel to the bulk sample surface to allow for direct correlation between mesoscale and microscale characterization. High dislocation density and the dislocation arrays in the slip bands corroborated with the first assumption. Evidence of plastic deformation in all grains, however, showed that the second assumption was false. Additionally, dislocation structures including crystal rotation boundaries and dislocations dissociating to the basal plane provide additional stress relief mechanisms near grain boundaries that are not accounted for in many crystal plasticity models, which requires auxiliary models to more accurately predict the stress and strain distribution in a microstructure.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Fading study of Harshaw LiF:Mg,Ti thermoluminescence dosimeters exposed to neutron doses

Sensitivity and signal fading were tested in Harshaw LiF:Mg,Ti thermoluminescence dosimeters (TLDs) exposed to neutron and beta/photons doses. A significant difference in the signal fading rate was observed for TLDs exposed to neutrons compared with TLDs exposed to betas. This difference may have been related to differences in glow curves for dosimeters exposed to different beams and to differences in glow curve evolution after exposure. A fading-correction algorithm was developed to correct the cumulative sensitivity + signal fading of TL doses for the fading time t using the formulae: y = 0.147∗exp(-t/4.36) + 0.308∗exp(-t/34.1) + 0.73 for neutrons, and: y = 0.132∗exp(-t/10.72) + 0.174∗exp(-t/31.5) + 0.8 for betas/photons. The formula was validated using the dose recovery test, where the average deviation of fading-corrected doses from delivery doses was within 1%. In conclusion, the proposed fading-correction approaches may significantly improve the accuracy of Harshaw TL dosimetry with LiF:Mg,Ti cards for both neutron and beta/gamma irradiation.

61 RADIATION PROTECTION AND DOSIMETRY↗