Developing an Optimized Homogenization Process for Sc and Zr Containing Al-Mg-Si Alloys

Babaniaris, Steven; Mariappan, R.; Jiang, Lu; Langan, Timothy; Dorin, Thomas

doi:10.1007/978-3-030-05864-7_181

Cited by 5 publications

(6 citation statements)

References 27 publications

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“…Micro-hardness and electrical conductivity measurements were carried out because they are very sensitive to changes of the dispersoid fraction, as well as the concentration of the alloying elements in a supersaturated solid solution. It should be noted that electrical conductivity is often used in studies related to aluminum alloys microalloying [ 36 , 37 , 38 ].…”

Section: Methodsmentioning

confidence: 99%

Alloying Elements Effect on the Recrystallization Process in Magnesium-Rich Aluminum Alloy

et al. 2022

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This paper addresses the study of the complex effect of alloying elements (magnesium, manganese, copper and zirconium) on changes in magnesium-rich aluminum alloy composition, fine and coarse particle size and number, recrystallization characteristics and mechanical properties. The data obtained made it possible to analyze change in the chemical composition, sizes of intermetallic compounds and dispersoids depending on alloying elements content. The effect of the chemical composition on the driving force and the number of recrystallization nuclei was studied. It was established that the addition of alloying elements leads to grain refinement, including through the activation of a particle-stimulated nucleation mechanism. As a result, with Mg increase from 4 to 5%, addition of 0.5% Mn and 0.5% Cu, the grain size decreased from 72 to 15 µm. Grain refinement occurred due to an increase in the number of particle-stimulated nuclei, the number of which at minimal alloying rose from 3.47 × 1011 to 81.2 × 1011 with the maximum concentration of Mg, Mn, Cu additives. The retarding force of recrystallization, which in the original alloy was 1.57 × 10−3 N/m2, increased to 5.49 × 10−3 N/m2 at maximum alloying. The influence of copper was especially noticeable, the introduction of 0.5% increasing the retarding force of recrystallization by 2.39 × 10−3 N/m2. This is due to the fact that copper has the most significant effect on the size and number of intermetallic particles. It was established that strength increase without ductility change occurs when magnesium, manganese and copper content increases.

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Section: Methodsmentioning

confidence: 99%

Alloying Elements Effect on the Recrystallization Process in Magnesium-Rich Aluminum Alloy

et al. 2022

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“…In this case, due to joint scandium-zirconium alloying, it is possible to improve the properties of the 6XXX group alloys even if the ratio of the wt. fractions is Mg/Si < 1.73 [25,30,31]. In alloys of the Al-Mg-Si system with ratio Mg/Si < 1.73, not all silicon combines with magnesium into the Mg2Si phase (or its metastable modifications such as β'') and there is an excess of it.…”

Section: Introductionmentioning

confidence: 99%

“…However, on the other hand, with the addition of scandium, excess silicon will increase the tendency to form AlSc2Si2. At the same time, the study of the processes occurring during casting and heat treatment of 6XXX group alloys with scandium-zirconium additives made it possible to avoid the undesirable phase and, in general, to improve the properties at a ratio Mg/Si ˃ 1.73 in AA6082 [26,30,32]. The possibility of further decreasing this ratio is promising since it will allow scandium and zirconium to be added to alloys such as 6016 where the excess of silicon is extremely large.…”

Section: Introductionmentioning

confidence: 99%

“…The possibility of further decreasing this ratio is promising since it will allow scandium and zirconium to be added to alloys such as 6016 where the excess of silicon is extremely large. However, it requires a thorough study on the effect of casting and thermomechanical treatment on the microstructure [26,30]. This article is devoted to the study of microstructure formation during casting of the 6XXX group alloys with a high silicon content and complex scandium and zirconium additives, especially in the range of element concentrations for which this problem has not yet be investigated.…”

Section: Introductionmentioning

confidence: 99%

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Influence of the Small Sc and Zr Additions on the As-Cast Microstructure of Al–Mg–Si Alloys with Excess Silicon

Aryshenskii

Lapshov

Hirsch

et al. 2021

Metals

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This research is devoted to the study effects of complex alloying of Al-0.3 wt. % Mg-1 wt. % Si and Al-0.5 wt. % Mg-1.3 wt. % Si alloys by small additions of Sc and Zr on the microstructure in the as-cast condition. The effect of small additions of these elements on the microhardness, electrical conductivity, grain size and phase composition of the indicated alloy systems was studied. The methods of optical and electron microscopy were used for the study. Moreover, the phase composition was calculated using the Thermo-Calc software package. The study showed a strong effect of the chemical composition of investigated alloys on the size of the grains, which, with a certain combination of additives, can decrease several times. Grain refinement occurs both due to supercooling and formation of primary Al3Sc particles in the liquid phase. Alloys based on Al-0.5 wt. % Mg-1.3 wt. % Si are more prone to the formation of this phase since a lower concentration of Sc is required for it to occur. In addition, more silicon interacts with other elements. At the same time, Al-0.3 wt. % Mg-1 wt. % Si requires lower temperature for complete dissolution of Mg2Si, which can contribute to more efficient heat treatment, which includes reducing the number of steps. TEM data show that during ingot cooling (AlSi)3ScZr dispersoid precipitates. This dispersoid could precipitate as coherent and semi-coherent particles with L12 structure as well as needle-shaped particles. The precipitation of coherent and semi-coherent particles during cooling of the ingot indicates that they can be obtained during subsequent multistage heat treatment. In addition, in the Al0.5Mg1.3Si0.3Sc alloy, metastable β″ (Mg5Si6) are precipitated.

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“…Therefore, it is promising to add Sc and Zr to alloys with high Si content. Some investigations show the positive effect of Sc and Zr additions to 6xxx-series alloys, even with an excess Si content [35,36]. However, such alloys require the careful selection of casting modes and multistage heat treatment, which makes it possible to sequentially obtain the strengthening particles (AlSi) 3 ScZr and β (Mg 5 Si 6 ).…”

Section: Introductionmentioning

confidence: 99%

The Casting Rate Impact on the Microstructure in Al–Mg–Si Alloy with Silicon Excess and Small Zr, Sc Additives

Aryshenskii

Lapshov

Konovalov

et al. 2021

Metals

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The study investigates the effect of casting speed on the solidification microstructure of the aluminum alloy Al0.3Mg1Si with and without the additions of zirconium and scandium. Casting was carried out in steel, copper, and water-cooled chill molds with a crystallization rate of 20 °C/s, 10 °C/s, and 30 °C/s, respectively. For each casting mode, the grain structure was investigated by optical microscopy and the intermetallic particles were investigated by scanning and transmission microscopy; in addition, measurements of the microhardness and the electrical conductivity were carried out. An increase in the solidification rate promotes grain refinement in both alloys. At the same time, the ingot cooling rate differently affects the number of intermetallic particles. In an alloy without scandium–zirconium additives, an increase in the ingot cooling rate leads to a decrease in the number of dispersoids due to an increase in the solubility of the alloying elements in a supersaturated solid solution. With the addition of scandium and zirconium, the amount of dispersoids increases slightly. This is because increasing the solubility of the alloying elements in a supersaturated solid solution is leveled by a growth of the number of grain boundaries, promoting the formation of particles of the (AlSi)3ScZr type, including those of the L12 type. In addition, the increase in the crystallization rate increases the number of primary nonequilibrium intermetallic particles which have a eutectic nature.

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Developing an Optimized Homogenization Process for Sc and Zr Containing Al-Mg-Si Alloys

Cited by 5 publications

References 27 publications

Alloying Elements Effect on the Recrystallization Process in Magnesium-Rich Aluminum Alloy

Alloying Elements Effect on the Recrystallization Process in Magnesium-Rich Aluminum Alloy

Influence of the Small Sc and Zr Additions on the As-Cast Microstructure of Al–Mg–Si Alloys with Excess Silicon

The Casting Rate Impact on the Microstructure in Al–Mg–Si Alloy with Silicon Excess and Small Zr, Sc Additives

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