Shape Factor Effect on Inclusion Sedimentation in Aluminum Melts

Gökelma, Mertol; Einarsrud, Kristian Etienne; Tranell, Gabriella; Friedrich, Bernd

doi:10.1007/s11663-020-01769-0

Cited by 6 publications

(2 citation statements)

References 17 publications

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“…where q p is the density of the ceramic platelets. The drag force can be written by the modified Stokes equation extended to non-spherical objects [40,41]:…”

Section: Separation Of the Ceramic Layer From The Steel Substratementioning

confidence: 99%

Spontaneous inversion of the submicron ceramic layer deposited on steel and the copper droplet positioned on their top (case of ceramic poorly wetted by liquid Cu)

et al. 2022

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In this paper, 50 … 680 nm thick AlN-Al2O3 coatings are deposited by magnetron sputtering on the surface of a steel substrate and a piece of copper is melted on top of the ceramic. Upon heating the ceramic layer is cracked, and the phase inversion of the two top phases from steel/ceramic/copper configuration to the steel/copper/ceramic configuration takes place within 30 s of liquid time of copper. This phase inversion process is accompanied by a Gibbs energy change of about − 1.78 J/m2, due to good wettability of solid deoxidized steel by liquid copper in contrary to poor wettability of the ceramic by the copper. When copper is melted on AlN-Al2O3 coating with its thicknesses smaller than a critical value of about 170 ± 60 nm, liquid copper droplets hanging down into the cracks within the ceramic reach the solid steel surface at the bottom of the cracks, thus the flow of Cu down along the cracks is enabled. However, when copper is melted on AlN-Al2O3 with its thickness larger than the critical value of 170 ± 60 nm, Cu first forms a non-wetting droplet on top of the ceramics, and only after a certain incubation time it starts flowing down the cracks. This incubation time was found to depend linearly on the thickness of the ceramic, as cracks are filled from the bottom upwards by liquid copper via the evaporation–condensation mechanism. By the end of the process, the steel/copper/ceramic configuration is further stabilized by gravity. Graphical abstract

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“…where q p is the density of the ceramic platelets. The drag force can be written by the modified Stokes equation extended to non-spherical objects [40,41]:…”

Section: Separation Of the Ceramic Layer From The Steel Substratementioning

confidence: 99%

Spontaneous inversion of the submicron ceramic layer deposited on steel and the copper droplet positioned on their top (case of ceramic poorly wetted by liquid Cu)

et al. 2022

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“…Settling of refiner particles in liquid aluminum alloys is one of the most common reasons for decreasing grain refining efficiency with time. The particle sedimentation process is dependent on the density of the solid particles relative to the liquid metal, the size distribution, and shape of the particles, the viscosity of the melt as well as the temperature distribution and convection inside the liquid alloy [ 16 , 17 , 18 , 19 , 20 ]. However, when grain refiner particle settling is considered, it should be taken into account that depending on its processing history, different amounts of native solid phases (inclusions) could be present in the liquid metal that could alter the sedimentation process [ 21 , 22 , 23 ].…”

Section: Introductionmentioning

confidence: 99%

Grain Refiner Settling and Its Effect on the Melt Quality of Aluminum Casting Alloys

Gyarmati

Bogoly²,

Stawarz³

et al. 2022

Materials

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Grain refiner particles, which are intended to induce the formation of fine equiaxed grain structure during the solidification of aluminum alloys, are prone to settling during the holding of the liquid metal, which phenomenon can affect not only the grain size but the spatial distribution of the double oxide films in the melt. In this study, the settling of Al3Ti inoculant particles, as well as its effects on melt quality and grain refinement, were studied. During the experiments, the Ti-concentration of a liquid Al-Si-Mg-Cu alloy was increased to 0.3 wt.% by the addition of Al-10%Ti master alloy at different melt temperatures. Particle settling and grain size evolution were studied by quantitative metallography, while the interactions of grain refiners and bifilms were investigated by scanning electron microscopy (SEM). The evolution of melt quality was assessed by the computed tomographic (CT) analysis of reduced pressure test (RPT) samples. It was found that effective grain refinement was only realized when the introduced blocky Al3Ti particles were dissolved and re-precipitated in the form of (Al,Si)3Ti at a lower temperature. Without dissolving at higher holding temperatures, Al3Ti particle settling has taken place within 10 min. The settling of (Al,Si)3Ti particles improved melt quality by the aided sedimentation of bifilms in the melt.

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Assessment of Separation and Agglomeration Tendency of Non-metallic Inclusions in an Electromagnetically Stirred Aluminum Melt

Liu

Dang

Gökelma

et al. 2023

The Minerals, Metals &Amp; Materials Series

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Shape Factor Effect on Inclusion Sedimentation in Aluminum Melts

Cited by 6 publications

References 17 publications

Spontaneous inversion of the submicron ceramic layer deposited on steel and the copper droplet positioned on their top (case of ceramic poorly wetted by liquid Cu)

Spontaneous inversion of the submicron ceramic layer deposited on steel and the copper droplet positioned on their top (case of ceramic poorly wetted by liquid Cu)

Grain Refiner Settling and Its Effect on the Melt Quality of Aluminum Casting Alloys

Assessment of Separation and Agglomeration Tendency of Non-metallic Inclusions in an Electromagnetically Stirred Aluminum Melt

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