Solidification Analysis of Al‐Si Alloys Modified with Addition of Cu Using In‐Situ Neutron Diffraction

Sediako, D.; Kasprzak, W.; Swainson, I. P.; Garlea, V. Ovidiu

doi:10.1002/9781118062142.ch35

Cited by 13 publications

(7 citation statements)

References 9 publications

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“…The Mg-6 wt.% Al alloy showed ~0.3 fraction solid at 600°C and around one at 590°C and below, to 420°C. For the Mg-6 wt.% Al, the fraction solid curve is similar to the plot observed in Al alloys [306,307] that tend to show a very rapid solid growth over a very short temperature interval. For the Mg-9 wt.% Al alloy the resulting fraction solid curve showed a gradual growth in Mg as the alloy is cooled over the investigated temperature range.…”

Section: Temp (°C)supporting

confidence: 70%

“…Neutrons behave similar to X-rays and electrons in that they obey Bragg's law for diffraction shown in Equation 28. Previous studies have examined the in-situ solidification of Al and its alloys using neutron diffraction [303][304][305][306][307][308][309]. Early research examined only the early stages of solidification and showed that TiB 2 addition increased the nucleation rate of Al by an order of magnitude as compared to a pure Al sample [303,304].…”

Section: Solidification Analysis Using In-situ Neutron Diffractionmentioning

confidence: 99%

“…More recent research examined the solidification of Al alloys over a wide temperature range in a step-wise fashion by holding the sample at each temperature for an extended period of time. In-situ neutron diffraction has shown to quantify the growth of primary Si and Al independently in an Al-19 wt.% Si alloy [306,307] not possible by using thermal analysis or metallographic techniques. In-situ neutron diffraction has also been used to detect Al 2 Cu formation and growth in a Al-Cu alloy and related to hot tearing mechanisms [308,309].…”

Section: Solidification Analysis Using In-situ Neutron Diffractionmentioning

confidence: 99%

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Inclusion removal and grain refinement of magnesium alloy castings

Elsayed¹

2021

Preprint

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Magnesium alloys show promise to be materials for lightweighting of automotive and aerospace vehicles improving fuel efficiencies and vehicle performance. A majority of magnesium alloy components are produced using casting where susceptibility to forming inclusions and coarse grain sizes could result. Development of effective inclusion removal techniques and better understanding of grain refinement of magnesium alloys could help in improving their mechanical properties to advance them to more structurally demanding applications. This research aimed to develop an environmentally friendly alternative to the grain refinement and inclusion removal capabilities of carbon based hexachloroethane as it releases dioxins, chlorine gas and corrodes foundry equipment. A secondary aim was to pioneer in-situ neutron diffraction to examine the solidification of magnesium alloys. The research involved preparing tensile samples of AZ91E magnesium alloy using permanent mould casting. Inclusion removal was conducted by using filtration and argon gas bubbling. Castings grain refined using hexachloroethane (0.25, 0.50 and 0.75 wt.%) were compared against ex-situ aluminum-silicon carbide and in-situ aluminum-carbon based grain refiners combined with filtration and argon gas bubbling. Further, in-situ neutron diffraction was utilized for phase analysis and fraction solid determination of magnesium-zinc and magnesium-aluminum alloys. There was a significant improvement in yield strength, ultimate tensile strength and elongation with filtration plus argon bubbling, carbon inoculation or both filtration plus argon bubbling and carbon inoculation. The results indicated that the mechanism of the observed ~20% reduction in grain sizes with carbon inoculation (hexachloroethane, ex-situ aluminum-silicon carbide and in-situ aluminum-carbon) was explained through duplex nucleation of Mn-Al and Al-Mg-C-O (likely Al2MgC2) phases. Finally, in-situ neutron diffraction was used to follow the formation of Mg17Al12 eutectic phase in a magnesium-9 wt.% aluminum alloy. For the magnesium-zinc alloys, in-situ neutron diffraction enabled characterization of the effects of zirconium to the fraction solid growth of (1010), (0002) and (1011) α-Mg planes. The societal and environmental impact of this research is significant. There is a clear demonstration of alternatives to the universally used hexachloroethane grain refiner promoting harmful emissions. Improved mechanical properties resulting from new grain refinement and iv inclusion filtration are a major advancement in promoting weight reduction, improved castability and decreased environmental impact for automotive and aerospace industries.

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Section: Temp (°C)supporting

confidence: 70%

Section: Solidification Analysis Using In-situ Neutron Diffractionmentioning

confidence: 99%

Section: Solidification Analysis Using In-situ Neutron Diffractionmentioning

confidence: 99%

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Inclusion removal and grain refinement of magnesium alloy castings

Elsayed¹

2021

Preprint

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“…[5][6][7] The results showed that neutron diffraction is advantageous over conventional thermal analysis techniques, as neutron diffraction was able to not only detect the nucleation of Si crystals before the nucleation of Al in Al-Si alloys but also to quantify the rate of primary Si evolution. This phenomenon is difficult to detect and impossible to quantify with conventional thermal analysis techniques.…”

Section: Introductionmentioning

confidence: 99%

Solidification analysis of Al–5 wt-%Cu alloy usingin situneutron diffraction

D’Elia

Ravindran

Sediako

et al. 2014

Canadian Metallurgical Quarterly

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In this study, in situ neutron diffraction was used to characterise the solidification of an Al-5 wt%Cu alloy. Neutron diffraction patterns were collected in a stepwise mode during solidification between 660 and 440uC. The nucleation and evolution of the primary Al phase and Al 2 Cu phase was successfully detected and quantified. The solid fractions of these phases were determined from the intensity of neutron diffraction peaks over the solidification interval. Furthermore, the results from neutron diffraction showed good agreement with FactSage simulations and optical and scanning electron microscopy. This study aims to better understand the solidification mechanism of Al-Cu alloys, with a view to eliminating the formation of defects during solidification and thereby, enhancing the use of Al-Cu alloys in industrial applications.Dans cette é tude, on a utilisé la diffraction des neutrons in situ pour caracté riser la solidification d'un alliage d'Al-5%Cu en poids. On a recueilli les figures de diffraction des neutrons en é tapes pendant la solidification entre 600 et 440uC. On a dé tecté avec succè s et quantifié la nuclé ation et l'é volution de la phase primaire d'Al et de la phase d'Al 2 Cu. On a dé terminé la fraction solide de ces phases à partir de l'intensité des pics de diffraction des neutrons dans l'intervalle de solidification. En plus, les ré sultats de la diffraction des neutrons montraient un bon accord avec les simulations de FactSage et avec la microscopie optique et é lectronique. Cette é tude vise à mieux comprendre le mé canisme de solidification des alliages d'Al-Cu, en vue d'é liminer la formation de dé fauts lors de la solidification et d'augmenter l'usage de ces alliages d'Al-Cu dans les applications industrielles.

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“…Studies examining the early stages of solidification showed that TiB 2 addition increased the nucleation rate of Al by an order of magnitude for Al alloys as compared to a pure Al sample [48,49]. In-situ neutron diffraction has also been utilized to quantify the growth of primary Si and Al independently in an Al-19 wt.% Si alloy [50,51] as well as to detect Al 2 Cu in Al-Cu alloys for hot tearing studies [52][53][54]. In-situ solidification studies of Al alloys using X-rays have been very useful because of their high resolution but are limited to the investigation of localized areas with attendant difficulties in producing sufficient elemental contrast in Al-Si based systems [55].…”

Section: Neutron Diffraction As a Tool For Materials Characterisationmentioning

confidence: 99%

Observing the Effect of Grain Refinement on Crystal Growth of Al and Mg Alloys during Solidification Using In-Situ Neutron Diffraction

Elsayed

D’Elia

Ravindran

et al. 2022

Metals

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The present research uses in-situ neutron diffraction to examine the effect of grain refinement on grain growth during solidification of Al-5 wt.% Cu and Mg-5 wt.% Zn alloys. The alloys were grain refined through additions of Al-5Ti-1B and Zr, respectively. The in-situ neutron diffraction experiments were carried out by heating the alloys to temperatures above the liquidus and subsequently cooling in 5 or 10 °C temperature steps to temperatures below solidus, while being irradiated by thermal neutrons. With the addition of grain refiners, grain size reductions of 92% were observed for both the Al-5 wt.% Cu and Mg-5 wt.% Zn alloys. The refined and unrefined Al-5 wt.% Cu alloys contained α-Al with Al2Cu along the grain boundary regions. Differences in Al2Cu morphology were observed in the grain refined alloys. The Mg-5 wt.% Zn alloy contained MgZn intermetallic phases with primary Mg. The refined Mg-5 wt.% Zn-0.7 wt.% Zr alloy contained Mg, MgZn and Zn2Zr phases. In-situ neutron diffraction enabled quantification of individual plane solid fraction growth for the α-Al and Al2Cu phases in the Al-Cu alloys, and for α-Mg in the Mg alloys. For the unrefined Al-5 wt.% Cu, the coarse microstructure resulted in a rapid solid fraction rise at temperatures just below liquidus followed by a gradual increase in solid fraction until the sample was fully solid. The grain-refined Al-5 wt.% Cu alloys showed a columnar to equiaxed microstructure transition and a more gradual growth in fraction solid throughout solidification. For the Mg-5 wt.% Zn alloy, the more packed (0002) and (101¯1) α-Mg plane intensities grew at a slower rate than the (101¯0) plane intensity, resulting in an irregular grain structure. With the addition of the Zr grain refiner, the Mg-5 wt.% Zn-0.7 wt.% Zr alloy had (101¯0), (0002) and (101¯1) planes intensities all increasing at similar rates, especially at the early stages of solidification. FactSage™ (version 6.4, Montréal, QC, Canada) equilibrium solidification models followed the fraction solid curves developed by tracking the fastest growing planes of the Mg alloys.

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Solidification Analysis of Al‐Si Alloys Modified with Addition of Cu Using In‐Situ Neutron Diffraction

Cited by 13 publications

References 9 publications

Inclusion removal and grain refinement of magnesium alloy castings

Inclusion removal and grain refinement of magnesium alloy castings

Solidification analysis of Al–5 wt-%Cu alloy usingin situneutron diffraction

Observing the Effect of Grain Refinement on Crystal Growth of Al and Mg Alloys during Solidification Using In-Situ Neutron Diffraction

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