High-purity Zirconium under Niobium ion implantation: possibility of a dynamic precipitation?

Revelly, A.K.; Becker, Hans‐Werner; Vishwanadh, B.; Krishna, K.V. Mani; Tewari, R.; Srivastava, D.; Dey, G.K.; Samajdar, I.; Panwar, Ajay S.

doi:10.1080/14786435.2015.1085132

Cited by 8 publications

(5 citation statements)

References 43 publications

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“…The lattice strain can be both elastic and plastic. Multiple { hkl } grazing incidence XRD (GIXRD) , is an effective means for evaluating stresses. Unlike the standard d sin 2 ψ, which is valid for a single X-ray pole, multiple { hkl } GIXRD covers all available poles and hence can be considered orientation independent.…”

Section: Resultsmentioning

confidence: 99%

High Thermoelectric Performance in Mg₂(Si_0.3Sn_0.7) by Enhanced Phonon Scattering

Goyal

Mukherjee²,

Mallik³

et al. 2019

ACS Appl. Energy Mater.

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Owing to the high thermoelectric (TE) conversion efficiency, low cost, and environmental friendliness Mg 2 Si 0.3 Sn 0.7 solid solution has emerged as the material of choice for the n-leg of a TE generator for midtemperature (room temperature to 800 K) applications. Dimensionless TE figure-of-merit (ZT) values of 1.3 (at 700 K) have been reported in this compound when optimally doped. High ZT values in this compound are due to a combination of improved electrical properties (band convergence effect) and reduced lattice thermal conductivity (alloy scattering of phonons). Here we demonstrate that the TE performance in this solid solution can be improved further (ZT max = 1.7 at T = 673 K, which is a record in silicide-based TE materials) by enhancing phonon scattering with embedded nanoprecipitates. The high ZT values are obtained when Mg 2 Si 0.3 Sn 0.7 is codoped with Bi and Cr. While Bi helps in optimizing the electrical transport properties, Cr results in formation of nanoprecipitates. Transmission electron microscopy (TEM) studies indicate embedded nanoprecipitates rich in elemental Cr and Sn. The nanoprecipitates also result in a strained interface as confirmed from high-resolution TEM (HRTEM) and grazing incidence XRD (GIXRD) studies. This results in an ∼15% reduction in the lattice thermal conductivity (κ L ) compared to the only Bi-doped sample while retaining similar power factor (S 2 σ) values. The overall effect is a ZT eng value of 0.73, which corresponds to a conversion efficiency (η) of 12% with the cold side temperature of 323 K and a ΔT = 350 K.

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Section: Resultsmentioning

confidence: 99%

High Thermoelectric Performance in Mg₂(Si_0.3Sn_0.7) by Enhanced Phonon Scattering

Goyal

Mukherjee²,

Mallik³

et al. 2019

ACS Appl. Energy Mater.

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“…The relaxation time used in this work is comparable to the previously used values for MD simulation studies for ion irradiation of materials. 22,46,47 Such a high value of current employed in the MD simulations, however, is 3 orders higher than the current used in the experiments (1.5 pA) and poses a limitation in the MD simulations. To employ a small current of 1.5 pA, a high relaxation time of the order of ∼10 5 ps would be required and is infeasible for currently available computation facilities.…”

Section: ■ Results and Discussionmentioning

confidence: 98%

Controlled Manipulation and Multiscale Modeling of Suspended Silicon Nanostructures under Site-Specific Ion Irradiation

Garg

Kamaliya

Singh

et al. 2020

ACS Appl. Mater. Interfaces

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In this work, controlled bidirectional deformation of suspended nanostructures by site-specific ion irradiation is presented. Multiscale modeling of the bidirectional deformation of nanostructures by site-specific ion irradiation is presented, incorporating molecular dynamics (MD) simulations together with finite element analysis, to substantiate the bending mechanism. Strain engineering of the free-standing nanostructure is employed for controlled deformation through site-specific kiloelectronvolt ion irradiation experimentally using a focused ion beam. We report the detailed bending mechanism of suspended silicon (Si) nanostructures through ion-induced irradiations. MD simulations are presented to understand the ion–solid interactions, defects formation in the silicon nanowire. The atomic-scale simulations reveal that the ion irradiation-induced bidirectional bending occurs through the development of localized tensile–compressive stresses in the lattice due to defect formation associated with atomic displacements. With an increasing ion dose, the evolution of localized tensile to compressive stress is observed, developing the alternate bending directions calculated through finite element analysis. The findings of multiscale modeling are in excellent agreement with the bidirectional nature of bending observed through the experiments. The developed in situ approach for bidirectional controlled manipulation of nanostructures in this work can be used for nanofabrication of numerous novel three-dimensional configurations and can provide a route toward functional nanostructures and devices.

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“…The patterns of residual stress evolution can be captured at different scales: from molecular dynamics (MD) to discrete dislocation dynamics (DDD) and crystal plasticity finite element (CPFEM). Revelly et al [34] used high-resolution transmission electron microscopy to experimentally measure shear residual stresses during ion irradiation. This was related to phase transformation, from hexagonal to body-centred cubic, at higher niobium flux.…”

Section: Discussion: Validating the Numerical Simulations And Beyondmentioning

confidence: 99%

Imposed thermal gradients and resultant residual stresses: Physical and numerical simulations

Mukherjee

Tewary

Kumar

et al. 2020

Materials Science and Technology

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In this study, physical simulations were carried out on High Strength Low Alloy (HSLA) steel specimens. Samples were heated above and below the austenite transformation temperature and then cooled at different rates. Thermal history and residual stress gradients were measured experimentally and simulated numerically. This involved finite element simulations, which solved the Fourier's heat conduction equation and also incorporated appropriate subroutines for phase transformations. The latter involved HETVAL, to quantify phase transformation, and USDFLD, to calculate the corresponding heat inputs. This manuscript not only established a similar pattern between the controlled experiments and the numerical simulations but also provided a quantitative perspective to residual stress gradients, as introduced by temperature gradients and by phase transformations, during thermomechanical processing.

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High-purity Zirconium under Niobium ion implantation: possibility of a dynamic precipitation?

Cited by 8 publications

References 43 publications

High Thermoelectric Performance in Mg₂(Si_0.3Sn_0.7) by Enhanced Phonon Scattering

High Thermoelectric Performance in Mg₂(Si_0.3Sn_0.7) by Enhanced Phonon Scattering

Controlled Manipulation and Multiscale Modeling of Suspended Silicon Nanostructures under Site-Specific Ion Irradiation

Imposed thermal gradients and resultant residual stresses: Physical and numerical simulations

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High-purity Zirconium under Niobium ion implantation: possibility of a dynamic precipitation?

Cited by 8 publications

References 43 publications

High Thermoelectric Performance in Mg2(Si0.3Sn0.7) by Enhanced Phonon Scattering

High Thermoelectric Performance in Mg2(Si0.3Sn0.7) by Enhanced Phonon Scattering

Controlled Manipulation and Multiscale Modeling of Suspended Silicon Nanostructures under Site-Specific Ion Irradiation

Imposed thermal gradients and resultant residual stresses: Physical and numerical simulations

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High Thermoelectric Performance in Mg₂(Si_0.3Sn_0.7) by Enhanced Phonon Scattering

High Thermoelectric Performance in Mg₂(Si_0.3Sn_0.7) by Enhanced Phonon Scattering