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Planar Defect Nucleation and Annihilation Mechanisms in Nanocontact Plasticity of Metal Surfaces
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Falsifiability Test for Classical Nucleation Theory
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Shear-driven motion of Mg { 10 1 ¯ 2 } twin boundaries via disconnection terrace nucleation, growth, and coalescence
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Atomistic modeling of LiF microstructure ionic conductivity and its influence on nucleation and plating
We report the formation and degradation of the solid electrolyte interphase (SEI) and its underlying transport properties play an essential role in the overall performance of lithium-ion batteries. This paper presents classical molecular dynamics studies on polycrystalline inorganic lithium fluoride (LiF) layers to model and predict the SEI transport properties. The ionic conductivity is obtained from the lithium-ion diffusivity in polycrystalline structures of LiF using the Nernst-Einstein relation. The predicted molecular dynamics data are used in a continuum scale phase-field model to evaluate the plating kinetics under fast charging conditions. The analysis emphasizes that the SEI ionic conductivity properties impact the plating dynamics, where SEI's low ion conductivity value is prone to large plating and subsequent capacity degradation. The combination of atomic and continuum scale studies shown herein lays a foundation to tune in SEI transport properties to decrease the amount of lithium plating and improve the performance of fast-charging batteries.
Nucleation and growth of polar clusters with in-phase tilts into a long-range ferroelectric matrix in a sodium niobate based complex relaxor
In this study, we have investigated the temperature dependence of atomic ordering at multiple length scales in a lead-free sodium niobate-based relaxor, i.e., 0.75 NaNbO 3 -0.25 Ba 0.9 Ca 0.1 TiO 3 (NN-25BCT) via synchrotron x-ray diffraction, Raman spectroscopy, and pair distribution function analysis. High-resolution synchrotron x-ray powder diffraction (SXRD) measurements reveal a ferroelectric phase transition in the relaxor ferroelectric NN-25BCT below the Vogel-Fulcher freezing temperature (𝑇 VF ≈ 270 K). In addition, SXRD analysis demonstrates the competition between in-phase octahedral tilting and ferroelectric order at the long-range scale using mode crystallography. On the other hand, Raman spectroscopic analysis provides evidence of polar ordering for 𝑇 > 𝑇 VF (with tetragonal symmetry) persisting up to the Burns temperature (𝑇 B ). Furthermore, pair distribution function (PDF) analysis reveals the presence of a polar antiferrodistortive tetragonal phase with 𝑃4𝑏𝑚 space group at short ranges throughout the studied temperatures (i.e., 110 K ≤ 𝑇 ≤500 K), irrespective of nonpolar long-range ordering above 𝑇 VF . Therefore, our measurements provide direct evidence for the presence of polar ordering at short ranges and their gradual transformation into long-range polar ordering using an integrated multiscale structural analysis. In conclusion, as a result of a transition from relaxor to a ferroelectric phase in the vicinity of room temperature, NN-25BCT can be exploited for applications in pyroelectric detectors, electrocaloric devices, and multilayered ceramic capacitors.
Crystal Growth for Beginners. Fundamentals of Nucleation, Crystal Growth and Epitaxy , 3rd edition . Edited by Ivan V Markov. World Scientific, 2017. Pp. 632. Hardback. Price GBP 123.00. ISBN 978-981-3143-42-5
Crystal growth is a classical discipline lying at the interfaces of Physics, Chemistry, Materials Science and Medicine. The research field has enjoyed an increasing number of young investigators over the past couple of decades, largely due to the burgeoning fields of nanoscience and nanotechnology which aim to fabricate nano-devices and/or to deliver nano-medicines in a process that mimics the exquisite wisdom of biologically controlled crystals. The interdisciplinary nature of these fields has posed a request for introductory monographs on the fundamental concepts of crystallization that are suitable for the diverse scientific backgrounds of researchers new to the field. Among many of the introductory crystal growth books, the Crystal Growth for Beginners (3rd edition) by Ivan Markov is an excellent one that can serve the purpose and is worth reading.
Microstructural Analysis of Spall Damage Nucleation and Growth in Multicrystalline Titanium
Abstract not provided
Response to Comment on “Reversible disorder-order transitions in atomic crystal nucleation”
Yu et al. suggested calculating precisely the size ranges of the three parts of our figure 3A, adjusting the free-energy levels in figure 3B, and considering the shape effect in the first-principles calculation. The first and second suggestions raise strong concerns for misinterpretation and overinterpretation of our experiments. Finally, the original calculation is sufficient to support our claim about crystalline-to-disordered transformations.
Effect of the Sapphire-Nitridation Level and Nucleation-Layer Enrichment with Aluminum on the Structural Properties of AlN Layers
The effect of atomic aluminum deposited onto sapphire substrates with different nitridation levels on the quality of AlN layers grown by ammonia molecular-beam epitaxy is investigated. The nitridation of sapphire with the formation of ~1 monolayer of AlN is shown to ensure the growth of layers with a smoother surface and better crystal quality than in the case of the formation of a nitrided AlN layer with a thickness of ~2 monolayers. It is demonstrated that the change in the duration of exposure of nitrided substrates to the atomic aluminum flux does not significantly affect the parameters of subsequent AlN layers.
Nonisothermal Nucleation in the Solid Solution CuCl in Glass: Temperature Range of the Formation of Supercritical Nuclei of CuCl Phase
It is established both experimentally and by calculations that the nuclei of CuCl phase do not form in the solid solution of CuCl in the glass at the temperature T{sub u} ≥ 600°C. At the temperature of 500°C, nuclei do not form due to a low diffusion coefficient. In the temperature range of 500–600°C maximums of the flow of new clusters and the critical radius are almost at the same temperature. The supersaturation is minimal in the area of maximum. The experimental dependence of the formation rate of CuCl clusters on temperature is in a good agreement with the calculated one. It is shown that the concentration of nuclei, its average radius, and the width of distribution by radii can be effectively controlled using the cooling “on the top.” The narrow distributions of CuCl clusters in the glass with the relative half-width of about 3.7% are obtained.
Mechanisms for Indirect Effects from Ice Nucleating Particles on Continental Clouds and Radiation
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Nucleation of fractal nanocrystallites upon annealing of Fe-based metallic glass
Abstract