On the mechanism of the formation of primary intermetallics under ultrasonic melt treatment in an Al-Zr-Ti alloy

Zhang, L; Eskin, Dmitry; Miroux, A.; Katgerman, L.

doi:10.1088/1757-899x/27/1/012002

Cited by 8 publications

(7 citation statements)

References 13 publications

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“…3c and d may suggest that some of the Al 3 Zr plates fragmented by cavitation may be fused with other fragments at the matching facet surface upon their travel in the melt due to the low melt temperature. The clustering or agglomeration of Al 3 Zr resembles the microstructure observed by Zhang et al 31 In their work, such Al 3 Zr agglomeration was typically found when a lower UST power was employed. This agglomeration was not observed anymore when the UST power was increased.…”

Section: Discussionsupporting

confidence: 71%

Structure Refinement Upon Ultrasonic Melt Treatment in a DC Casting Launder

Subroto

Eskin

Beckwith

et al. 2020

JOM

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This work focuses on ultrasonic melt treatment (UST) in a launder upon pilotscale direct chill (DC) casting of 152-mm-diameter billets from an AA6XXX alloy with Zr addition. Two casting temperatures (650°C and 665°C) were used to assess their effect on the resulting microstructure (grain size, particle size, and number density). Structure refinement results show the feasibility of UST in the DC casting launder. This is quantified through the corresponding reduction of grain size by around 50% in the billet center, or more towards the billet surface, reduction of the average Al 3 Zr particle size, and increase in the particle number density. A higher Al 3 Zr particle density was obtained when the alloy was cast at 665°C. Numerical simulation results and suggestions on how to improve the treatment quality of UST in DC casting launder are also provided.

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Section: Discussionsupporting

confidence: 71%

Structure Refinement Upon Ultrasonic Melt Treatment in a DC Casting Launder

Subroto

Eskin

Beckwith

et al. 2020

JOM

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“…% leads to the formation of primary Al 3 Zr particles in the as-cast structure and negatively affects the properties of the investigated alloys. The same results are reported in [21][22][23]. Furthermore, the appearance of the primary Al 3 Zr can also be associated with such disadvantages of the alloy production regime as casting temperature and cooling rate.…”

Section: Discussionsupporting

confidence: 79%

“…According to Equation (1), the strengthening effect from the metastable nanoscale Al 3 Zr L1 2 dispersoids with an average size of 10 nm was 17-times higher compared to the stable incoherent plate-like D0 23 Al 3 Zr particles with a length equal to 200 nm and a thickness of about 50 nm ( Figure 6). Kendig et al also reported that the maximum hardening is achieved with the size of precipitates Al 3 Zr at 5-10 nm [26].…”

Section: Discussionmentioning

confidence: 99%

Effect of Si and Zr on the Microstructure and Properties of Al-Fe-Si-Zr Alloys

Morozova

Mogucheva

Bukin

et al. 2017

Metals

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Abstract:The effects of Si and Zr on the microstructure, microhardness and electrical conductivity of Al-Fe-Si-Zr alloys were studied. An increase in the Zr content over 0.3 wt. % leads to the formation of primary Al 3 Zr inclusions and also decreases mechanical properties. Therefore, the Zr content should not be more than 0.3 wt. %, although the smaller content is insufficient for the strengthening by the secondary Al 3 Zr precipitates. The present results indicate that high content of Si significantly affects the hardness and electrical conductivity of the investigated alloys. However, the absence of Si led to the formation of harmful needle-shaped Al 3 Fe particles in the microstructure of the investigated alloys after annealing. Therefore, the optimum amount of Si was 0.25-0.50 wt. % due to the formation of the Al 8 Fe 2 Si phase with the preferable platelet morphology. The maximum microhardness and strengthening effects in Al-1% Fe-0.25% Si-0.3% Zr were observed after annealing at 400-450 • C due to the formation of nanosized coherent Al 3 Zr (L1 2 ) dispersoids. The effect of the increasing of the electrical conductivity can be explained by the decomposition of the solid solution. Thus, Al-1% Fe-0.25% Si-0.3% Zr alloy annealed at 450 • C has been studied in detail as the most attractive with respect to the special focus on transmission line applications.

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“…High frequency and high amplitude oscillations result in cavitation of the melt and also promote intense mixing through agitation [10,11]. The reported mechanisms are related either to increasing the number of nucleation sites or to improving the nucleant potency of the particles [10][11][12][13][14][15]. Our previous results show that when transition metals Zr and Ti are present in the melt, UST becomes very efficient for grain refinement in aluminum alloys, especially when it is performed in the temperature range of primary solidification of Al 3 Zr [12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

“…The reported mechanisms are related either to increasing the number of nucleation sites or to improving the nucleant potency of the particles [10][11][12][13][14][15]. Our previous results show that when transition metals Zr and Ti are present in the melt, UST becomes very efficient for grain refinement in aluminum alloys, especially when it is performed in the temperature range of primary solidification of Al 3 Zr [12][13][14][15]. The ultrasonicaided grain refinement in the alloys containing Zr and Ti was related to the refinement of primary Al 3 (Zr,Ti) intermetallics upon cavitation, significant increase of their number and further involvement in solidification as nucleation sites for aluminum.…”

Section: Introductionmentioning

confidence: 99%

Role of Solute and Transition Metals in Grain Refinement of Aluminum Alloys under Ultrasonic Melt Treatment

Zhang

Eskin

Miroux

et al. 2012

ICAA13: 13th International Conference on Aluminum Alloys

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It is well known that several factors affect the as-cast microstructure through influencing either nucleation or growth during solidification. The effect of solute elements on grain refinement, which can be quantified by the growth restriction parameter Q, is of great importance for controlling the as-cast grain size in aluminum alloy. On the other hand, the ultrasonic melt treatment (UST) is one of potent grain refining methods in aluminum alloy. Our previous results showed that ultrasonic melt treatment results in a significant grain refining effect in an aluminum alloy when transition metals, such as Ti and Zr, are present in the melt. It was suggested that UST may increase the nucleating potency of Al 3 (Zr,Ti) intermetallics. In this paper, the growth restriction effect caused by segregating elements is considered in order to further study the efficiency and potency of grain refiner particles caused by ultrasonic treatment. The results show that the main effect of transition metals Zr and Ti is related to the maximum number of particles which are active nucleants under UST. With increasing Zr, the maximum number of potent particles increases, which produces a better grain refining effect.

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On the mechanism of the formation of primary intermetallics under ultrasonic melt treatment in an Al-Zr-Ti alloy

Cited by 8 publications

References 13 publications

Structure Refinement Upon Ultrasonic Melt Treatment in a DC Casting Launder

Structure Refinement Upon Ultrasonic Melt Treatment in a DC Casting Launder

Effect of Si and Zr on the Microstructure and Properties of Al-Fe-Si-Zr Alloys

Role of Solute and Transition Metals in Grain Refinement of Aluminum Alloys under Ultrasonic Melt Treatment

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