Mechanical Spectroscopy Investigation of Liquid Pb-Bi Alloys

Montanari, Roberto; Varone, Alessandra

doi:10.4028/www.scientific.net/ssp.184.434

Cited by 15 publications

(16 citation statements)

References 17 publications

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“…The evolution of the liquid structure is consistent with anelastic phenomena, occurring in the temperature range examined here, i.e. the relevant modulus change and the IF maxima observed by means of mechanical spectroscopy.…”

Section: Discussionsupporting

confidence: 86%

“…The temperature range, where diffusion processes lead to the disgregation of clusters, corresponds to that of relevant change of modulus and internal friction (IF) maxima observed by mechanical spectroscopy . Therefore, it is reasonable to ascribe the anelastic behaviour of liquid alloy to the atomic diffusion from the clusters to matrix.…”

Section: Resultsmentioning

confidence: 93%

“…The investigations by using mechanical spectroscopy and high‐temperature X‐ray diffraction have evidenced that the structure of liquid alloy undergoes relevant changes as the temperature is increased.…”

Section: Introductionmentioning

confidence: 99%

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Microchemical inhomogeneity in eutectic Pb–Bi alloy quenched from melt

Mezzi¹,

Kačiulis²,

Balijepalli

et al. 2014

Surface & Interface Analysis

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The liquid lead-bismuth eutectic alloy is of great interest for applications in advanced nuclear systems; in particular, it is considered to be a good candidate as a coolant and neutron spallation source material for MYRRHA (http://myrrha.sckcen.be/), an accelerator driven system. Investigations based on mechanical spectroscopy experiments and high-temperature X-ray diffraction evidenced that the structure of the liquid alloy is not stable but undergoes relevant changes as the temperature increases. To understand whether such transformations, occurring in the liquid state involve elemental clustering, the alloy has been waterquenched from the liquid state at three different temperatures. After quenching, the samples have been investigated by standard XPS and scanning photoemission microscopy at the ELETTRA synchrotron. The SPEM results showed that the distribution of two metals is characterised by the following: (i) Pb-enriched clusters, (ii) Bi-enriched clusters and (iii) matrix in near eutectic composition. The statistics of clusters size was evaluated from the linescans of chemical Pb/Bi images. The average size of clusters is noticeably reduced by increasing quenching temperature: it is in the range of 1 ÷ 3 μm at 313°C and passes to 0.5 ÷ 0.9 μm at 518°C. Therefore, scanning photoemission microscopy results evidenced a structural and microchemical rearrangement of the atoms in the melt consisting in the evolution of cluster size and composition.

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Section: Discussionsupporting

confidence: 86%

Section: Resultsmentioning

confidence: 93%

See 1 more Smart Citation

Microchemical inhomogeneity in eutectic Pb–Bi alloy quenched from melt

Mezzi¹,

Kačiulis²,

Balijepalli

et al. 2014

Surface & Interface Analysis

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show abstract

“…In previous work, MS tests showed a relevant change in the microstructure of liquid LBE [38]. In the same material, a damping maximum at ~550 °C has been recorded by Zu et al [33] and ascribed to a structural change occurring when, above a critical temperature, the alloy, that still has minor residual crystals after melting, transforms into a configuration without crystalline conglomerates.…”

Section: Introductionmentioning

confidence: 61%

Lead-Bismuth Eutectic: Atomic and Micro-Scale Melt Evolution

et al. 2019

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Element clustering and structural features of liquid lead-bismuth eutectic (LBE) alloy have been investigated up to 720 °C by means of high temperature X-ray diffraction (HT-XRD), X-ray Photoemission Spectroscopy (XPS) and Scanning Photoemission Microscopy (SPEM) at the Elettra synchrotron in Trieste. The short-range order in liquid metal after melting corresponds to the cuboctahedral atomic arrangement and progressively evolves towards the icosahedral one as temperature increases. Such process, that involve a negative expansion of the alloy, is mainly connected to the reduction of atom distance in Pb–Pb pairs which takes place from 350 °C to 520 °C. On an atomic scale, it is observed a change of the relative number of Bi–Bi, Pb–Pb, and Pb–Bi pairs. The Pb–Bi pairs are detected only at a temperature above ~350 °C, and its fraction progressively increases, giving rise to a more homogeneous distribution of the elements. SPEM results showed evidence that the process of chemical homogenization on an atomic scale is preceded and accompanied by homogenization on micro-scale. Clusters rich of Bi and Pb, which are observed after melting, progressively dissolve as temperature increases: Only a few residuals remain at 350 °C, and no more clusters are detected a 520 °C.

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“…It is noteworthy to remind that few data from MS tests on liquid metals are reported in the literature [17] and have been obtained by means of a modified inverted torsion pendulum operated by forced oscillations. The present experiments have been done by using a new method developed by us [18,19]; it operates in resonance conditions and employs hollow reeds of stainless steel containing the liquid metal.…”

Section: Introductionmentioning

confidence: 99%

Synergic Role of Self-Interstitials and Vacancies in Indium Melting

Montanari

Varone

2015

Metals

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Precursor effects of indium melting have been investigated by means of Mechanical Spectroscopy (MS) and High Temperature X-ray Diffraction (HT-XRD). MS tests evidenced a sharp drop of dynamic modulus in the temperature range between 418 K and 429 K (melting point). At 429 K, HT-XRD showed partial grain re-orientation, peak profile broadening, in particular in the lower part, and peak shift towards lower angles. Experimental results are consistent with density increase of self-interstitials and vacancies in the crystal lattice before melting. Self-interstitials and vacancies play a synergic role in the solid-liquid (S-L) transformation. The increase of self-interstitials over a temperature range of about 10 K before melting has the effect of weakening interatomic bonds (modulus drop) that favors the successive vacancy formation. Finally, the huge increase of vacancy concentration above 428 K leads to the collapse of crystal lattice (melting).

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Mechanical Spectroscopy Investigation of Liquid Pb-Bi Alloys

Cited by 15 publications

References 17 publications

Microchemical inhomogeneity in eutectic Pb–Bi alloy quenched from melt

Microchemical inhomogeneity in eutectic Pb–Bi alloy quenched from melt

Lead-Bismuth Eutectic: Atomic and Micro-Scale Melt Evolution

Synergic Role of Self-Interstitials and Vacancies in Indium Melting

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