Nanosized Lead Inclusions in Aluminum-Magic Sizes and Aspect Ratios

Johnson, Erik; Johansen, Å.; Dahmen, U.; Chen, Shi Jin; Fujii, T.

doi:10.4028/www.scientific.net/msf.294-296.115

Cited by 12 publications

(7 citation statements)

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“…The results are similar to two phase lead-tin inclusions in aluminum produced by ion implantation. 4 Johnson et al 4 have reported the formation of two phase lead-tin particles attached along internal {111} fcc interface. Their results show that Pb has fcc structure and is oriented in parallel cube alignment with Al matrix, whereas the orientation of Sn has not been established.…”

Section: Bhattacharya and Chattopadhyaymentioning

confidence: 99%

Phase Transformation in Nanoscale Indium–Tin Alloy Particles Embedded in Metallic Matrices

Bhattacharya

Chattopadhyay²

2007

j nanosci nanotechnol

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The interfaces influence the phase stability of small particles. For embedded indium-tin alloy particles, the interface among the phases present within the particles and the matrix contribute significantly to the free energy and hence influences the phase stability at small sizes. Our results show that upon rapid cooling, we obtain a combination of larger two-phase alloy particles consisting of beta- and y-phases and very fine precipitates of In or Sn. Both beta- and gamma-phases possess an orientation relationship with Al. The in situ results suggest that the beta-rich phase gradually dissolved in the eutectic liquid before melting and the particles retain the facets much above the melting temperature of the alloy particle. We have tried to explain the formation and stability of these phases in terms of favorable nucleation kinetics.

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Section: Bhattacharya and Chattopadhyaymentioning

confidence: 99%

Phase Transformation in Nanoscale Indium–Tin Alloy Particles Embedded in Metallic Matrices

Bhattacharya

Chattopadhyay²

2007

j nanosci nanotechnol

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“…Since all inclusions are parallel to the matrix lattice but isolated from each other by the limited solid solubility, the Al matrix acts as an alignment field and an isolating medium. In the nanoscale size regime, solid Pb inclusions display magic size behavior [3], and their equilibrium shape is affected by the edge energy of the faceted shapes [4]. Solid inclusions at grain boundaries were found to adopt compound shapes that depend on the crystallographic characteristics of the grain boundary [5].…”

Section: Introductionmentioning

confidence: 99%

Equilibrium shape and interface roughening of small liquid Pb inclusions in solid Al

et al. 2001

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The shape of liquid Pb inclusions embedded in a solid Al matrix was investigated at temperatures between 300 and 500°C using in-situ electron microscopy. Inclusion shapes in the size range from a few nanometers to about 150 nanometers were found to depend on size, temperature and thermal history. During isothermal annealing after melting, small inclusions rounded off while larger inclusions remained faceted until the temperature was raised to about 500°C. During subsequent cooling, inclusions refaceted, although less strongly than during heating. The shape hysteresis between heating and cooling cycles was found to be due to the barrier of ledge nucleation necessary to advance the faceted interfaces. It is shown that this kinetic barrier can explain the observed dependence on size and temperature, and that the {111} interface undergoes a roughening transition at about 550°C. Even under conditions of kinetic limitation it was possible to measure local equilibrium by modeling kinetically limited inclusions as a droplet in a crevice. For this type of measurement, the hysteresis between heating and cooling cycles disappeared, and the true equilibrium shape could be derived. The anisotropy of interfacial energy was shown to be significantly smaller than previously reported, and at about 2 %, similar to the anisotropy of the surface energy for fcc metals.From the width of facets on the equilibrium shape, the step energy was determined to be at 350°C. ε = 1.9⋅10 -11 J / m 1 9/29/00

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“…In the previously considered case of facetted Pb nanoparticles that are embedded in an Al matrix with a cube‐on‐cube orientation relationship obeyed, two additional contributions to the interface energy were considered: a residual strain energy which gives rise to a “magic size effect,” and a term considering the contribution of the edge energy of the faceted shape, which renders the aspect ratio ρ size dependent. [ 31,43,89 ] It should, however, be considered that the total excess strain energy stored in these Al–Pb interfaces is based on misfit‐dislocations that reduce the total residual (misfit) strain. [ 90 ] It was reported that this strain effect caused the observed scattering of the aspect ratio.…”

Section: Size‐dependent Melting and The Interface Structurementioning

confidence: 99%

Structural Phase Transformations in Nanoscale Systems

Wilde

2021

Adv Eng Mater

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As characteristic size scales of materials systems tend to progressively become shorter, size‐dependent materials’ behavior becomes increasingly important. Related to many aspects concerning stability, function, and performance are phase transformations that might be necessary to obtain a specific state or are necessary to avoid to retain a specific phase or state with desired properties. At dimensions in the range of tens nanometers or below, size effects affect structural phase transformations significantly. Opinions and models about the origin of the size‐dependence abound since several decades. However, more recent results allow analyzing the local atomic structure of the particle/matrix interfaces as well as local strain contributions in detail. In addition, size‐dependent measurements of excess thermodynamic potentials can be carried out and rate‐dependent analyses explore new regimes at significantly enhanced heating rates. These recent results serve to estimate the relative importance of kinetic and different thermodynamic contributions. Herein, the emphasis is on summarizing the recent progress that is made on the size effect and on the impact of the interfacial structure on the melting transformation of embedded nanoparticles. At the same time, these results serve to considerably enhance the understanding of the melting process in general.

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Nanosized Lead Inclusions in Aluminum-Magic Sizes and Aspect Ratios

Cited by 12 publications

References 0 publications

Phase Transformation in Nanoscale Indium–Tin Alloy Particles Embedded in Metallic Matrices

Phase Transformation in Nanoscale Indium–Tin Alloy Particles Embedded in Metallic Matrices

Equilibrium shape and interface roughening of small liquid Pb inclusions in solid Al

Structural Phase Transformations in Nanoscale Systems

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