Nanoscale phase separation in epitaxial Cr-Mo and Cr-V alloy thin films studied using atom probe tomography: Comparison of experiments and simulation

Devaraj, Arun; Kaspar, Tiffany C.; Ramanan, Sathvik; Walvekar, Sarita K.; Bowden, Mark E.; Shutthanandan, V.; Kurtz, Richard J.

doi:10.1063/1.4901465

Cited by 13 publications

(9 citation statements)

References 38 publications

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“…Pearson coefficient test can be used to measure the statistical relevance of the observed deviation from randomness 52 53 54 . Pearson coefficients tending towards 1 indicate statistically relevant extent of compositional segregation 52 55 . The Pearson coefficients for elemental Li and Ni obtained from the 200-atom bin size frequency distribution analysis were 0.869 and 0.792, respectively; Mn and O had Pearson coefficient of 0.253 and 0.391, respectively.…”

Section: Resultsmentioning

confidence: 99%

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Visualizing nanoscale 3D compositional fluctuation of lithium in advanced lithium-ion battery cathodes

et al. 2015

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The distribution of cations in Li-ion battery cathodes as a function of cycling is a pivotal characteristic of battery performance. The transition metal cation distribution has been shown to affect cathode performance; however, Li is notoriously challenging to characterize with typical imaging techniques. Here laser-assisted atom probe tomography (APT) is used to map the three-dimensional distribution of Li at a sub-nanometre spatial resolution and correlate it with the distribution of the transition metal cations (M) and the oxygen. As-fabricated layered Li1.2Ni0.2Mn0.6O2 is shown to have Li-rich Li2MO3 phase regions and Li-depleted Li(Ni0.5Mn0.5)O2 regions. Cycled material has an overall loss of Li in addition to Ni-, Mn- and Li-rich regions. Spinel LiNi0.5Mn1.5O4 is shown to have a uniform distribution of all cations. APT results were compared to energy dispersive spectroscopy mapping with a scanning transmission electron microscope to confirm the transition metal cation distribution.

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Section: Resultsmentioning

confidence: 99%

“…The Pearson coefficient estimated for all the molecular species were also well below 0.1. A Pearson coefficient value close to 0 is indicative of a uniform distribution of elements 52 55 . The P values estimated at a 95% confidence interval for Li and O was observed to be below 0.001 and the P value for Mn and Ni were 0.095 and 0.568.…”

Section: Resultsmentioning

confidence: 99%

Visualizing nanoscale 3D compositional fluctuation of lithium in advanced lithium-ion battery cathodes

et al. 2015

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“…Another significant and unique contribution of APT has been for aiding in compositional quantification of phase separation in alloys by spinodal decomposition [165][166][167]. APT can provide quantitative information on the amplitude and wavelength of the compositional modulations as a function of time in alloy systems prone to spinodal decomposition [168][169][170][171][172].…”

Section: Applications Of Apt In Materials Analysismentioning

confidence: 99%

Three-dimensional nanoscale characterisation of materials by atom probe tomography

Devaraj

Perea

Liu

et al. 2017

International Materials Reviews

136

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The development of three-dimensional (3-D), characterisation techniques with high spatial and mass resolution is crucial for understanding and developing advanced materials for many engineering applications as well as for understanding natural materials. In recent decades, atom probe tomography (APT), which combines a point projection microscope and time-offlight mass spectrometer, has evolved to be an excellent characterisation technique capable of providing 3-D nanoscale characterisation of materials with sub-nanometer scale spatial resolution, with equal sensitivity for all elements. This review discusses the current state, as of APT instrumentation, new developments in sample preparation methods, experimental procedures for different material classes, reconstruction of APT results, the current status of correlative microscopy, and application of APT for microstructural characterisation in established scientific areas like structural materials as well as new applications in semiconducting nanowires, semiconductor devices, battery materials, catalyst materials, geological materials, and biological materials. Finally, a brief perspective is given regarding the future of APT.

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“…Here, atom probe microscopy (APM) represents a powerful tool for the detailed study of the complex nanoscale morphology of superalloys, even beyond the standard three-dimensional characterization with quasi-atomic resolution (Gault et al, 2012 a ). For example, cluster search algorithms provide quantitative insights into clustering of solute atoms by their Pearson coefficients (Moody et al, 2008; Devaraj et al, 2014). Precipitates have been studied revealing their morphology and chemical composition in materials including Al-, Fe-, and Ni-alloys (Blavette et al, 2000; Jiang et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Atom Probe Microscopy of Strengthening Effects in Alloy 718

2019

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Polycrystalline Ni-based superalloys for aerospace and power generation applications are often precipitation hardened to achieve strengthening at elevated temperatures. Here, atom probe microscopy has become an essential tool to study the complex morphology of nanoscale precipitates. This study focuses on Alloy 718, which is hardened by semi-coherent, ordered γ′ (Ni3(Al, Ti)) and γ″ (Ni3(Nb)) particles. According to previous research, these particles often occur as duplets or triplets with a stacking sequence dependent on prior processing. This creates various interfaces with a strong impact on the mechanical properties, highlighting the importance of quantitative studies which are challenging with electron microscopy. We present atom probe data reconstruction and analysis approaches particularly suited for precipitation hardened superalloys. While voltage atom probe allows for an accurate reconstruction, the acquired data volume is often limited. Laser-assisted atom probe provides statistically significant data, but the loss of crystallographic information requires correlation with voltage-mode datasets. We further describe an advanced iso-surface method where initially arbitrarily chosen concentration thresholds of Al + Ti for γ′ and Nb for γ″ particles are optimized. Recognizing the importance of the precipitate stacking order, the different types of precipitate interfaces are quantified, and these methods may be applicable to other engineering alloys.

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Nanoscale phase separation in epitaxial Cr-Mo and Cr-V alloy thin films studied using atom probe tomography: Comparison of experiments and simulation

Cited by 13 publications

References 38 publications

Visualizing nanoscale 3D compositional fluctuation of lithium in advanced lithium-ion battery cathodes

Visualizing nanoscale 3D compositional fluctuation of lithium in advanced lithium-ion battery cathodes

Three-dimensional nanoscale characterisation of materials by atom probe tomography

Atom Probe Microscopy of Strengthening Effects in Alloy 718

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