Criteria of Grain Refinement Induced by Ultrasonic Melt Treatment of Aluminum Alloys Containing Zr and Ti

Atamanenko, T.V.; Eskin, Dmitry; Zhang, L.; Katgerman, L.

doi:10.1007/s11661-010-0232-4

Cited by 237 publications

(187 citation statements)

References 20 publications

Supporting

Mentioning

177

Contrasting

Order By: Relevance

“…It has been suggested and demonstrated that ultrasonic treatment results in fragmentation of primary intermetallics, increasing their number [8][9][10]. In order to analyze the effect of ultrasonic treatment on formation of Al 3 Ti and related grain refinement in a hyperperitectic Al-Ti alloy, the Al-0.4 wt% Ti alloy was subjected to UST in the solidification range of Al 3 Ti, from 720 to 680°C.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Influence of ultrasonic melt treatment on the formation of primary intermetallics and related grain refinement in aluminum alloys

2011

Self Cite

View full text Add to dashboard Cite

Ultrasonic melt treatment (UST) is known to induce grain refining in aluminum alloys. Previous studies have clearly shown that in Al-Zr-Ti alloys, the primary Al 3 Zr intermetallics were dramatically refined by cavitation-assisted fragmentation, and a good refinement effect was achieved. In this article, Al-Ti, Al-Ti-Zr alloys, and some commercial aluminum alloys are used to analyze the effect of UST on primary intermetallics and grain refinement. The addition of a small amount of Al-3Ti-B master alloy is also studied in order to compare with the addition of Ti and Zr in commercial aluminum alloys. Experimental results show that the ultrasonic grain refining effect is not only related to the size of particles which are refined and/or dispersed by UST, but also related to an undercooling available for activation of these particles in the solidification process. Athermal heterogeneous nucleation theory is considered to explain the effect of size and distribution of substrate particles on the grain structure with different undercoolings. The distribution of primary particle sizes results in the distribution of required undercoolings. Grain refining occurs when the undercooling is large enough to activate the refined primary intermetallics or dispersed inoculants.

show abstract

Section: Resultsmentioning

confidence: 99%

“…Aluminum grain refinement occurs when the UST is performed in the temperature range of primary solidification of Al 3 (Zr, Ti) [9]. The suggested mechanisms include the heterogeneous nucleation of (Al) on smaller intermetallic particles at higher undercooling [10].…”

Section: Introductionmentioning

confidence: 99%

Influence of ultrasonic melt treatment on the formation of primary intermetallics and related grain refinement in aluminum alloys

2011

Self Cite

View full text Add to dashboard Cite

show abstract

“…[1][2][3] Although ultrasound-induced grain refinement has been shown effective in many metallic alloy systems, almost all previous research have interpreted the mechanism of grain refinement based on post-mortem microstructural characterization of the solidified alloys and empirical correlation, if any, between the measured grain size and the input ultrasonic power. [4,5] A very recent high-speed imaging study of ultrasonic treatment of a solidifying organic transparent alloy revealed that the shock wave emitted from imploding bubbles can fracture the growing dendrites, [6] increasing the grain multiplication effect that leads to the enhancement of grain refinement. However, in situ and real time studies of the fundamentals of how the highly dynamic ultrasonic waves and the ultrasonic bubbles interact with the liquid metal, the semisolid and solid phases nucleated during solidification have not been reported mainly due to the difficulties in studying the bubble dynamics in the opaque liquid metal.…”

Section: Applying Ultrasonic Waves Inside Liquid Mediamentioning

confidence: 99%

In Situ Synchrotron X-ray Study of Ultrasound Cavitation and Its Effect on Solidification Microstructures

Tan

Lee

2014

Metall Mater Trans B

View full text Add to dashboard Cite

Considerable progress has been made in studying the mechanism and effectiveness of using ultrasound waves to manipulate the solidification microstructures of metallic alloys. However, uncertainties remain in both the underlying physics of how microstructures evolve under ultrasonic waves, and the best technological approach to control the final microstructures and properties. We used the ultrafast synchrotron X-ray phase contrast imaging facility housed at the Advanced Photon Source, Argonne National Laboratory, US to study in situ the highly transient and dynamic interactions between the liquid metal and ultrasonic waves/bubbles. The dynamics of ultrasonic bubbles in liquid metal and their interactions with the solidifying phases in a transparent alloy were captured in situ. The experiments were complemented by the simulations of the acoustic pressure field, the pulsing of the bubbles, and the associated forces acting onto the solidifying dendrites. The study provides more quantitative understanding on how ultrasonic waves/bubbles influence the growth of dendritic grains and promote the grain multiplication effect for grain refinement. have been widely used in industry, e.g., in ultrasonic cleaning, sonochemistry, and medical treatment. In the past few decades, extensive laboratory results have demonstrated that applying ultrasound waves into solidifying liquid alloys can lead to the refinement of alloy microstructures. [1][2][3] Although ultrasound-induced grain refinement has been shown effective in many metallic alloy systems, almost all previous research have interpreted the mechanism of grain refinement based on post-mortem microstructural characterization of the solidified alloys and empirical correlation, if any, between the measured grain size and the input ultrasonic power. [4,5] A very recent high-speed imaging study of ultrasonic treatment of a solidifying organic transparent alloy revealed that the shock wave emitted from imploding bubbles can fracture the growing dendrites, [6] increasing the grain multiplication effect that leads to the enhancement of grain refinement. However, in situ and real time studies of the fundamentals of how the highly dynamic ultrasonic waves and the ultrasonic bubbles interact with the liquid metal, the semisolid and solid phases nucleated during solidification have not been reported mainly due to the difficulties in studying the bubble dynamics in the opaque liquid metal. In this paper, we report a number of in situ imaging studies of the dynamic behavior of ultrasonic bubbles in a Sn-13 wt pct Bi and a Bi-8 wt pct Zn alloy using the ultrafast X-ray phase contrast imaging (PCI) facility housed at the Advanced Photon Source (APS), Argonne National Laboratory, US. The real-time imaging studies are complemented by a numerical simulation of the bubble dynamics using the classical Gilmore model. [7] The experiments were carried out at the beamline 32-ID-B of APS, and the detailed description of the experiment can be found in References 8, 9. The undulator gap was set to 14 ...

show abstract

“…Their results indicated that the wetted side of an oxide film can act as nucleation sites for the Fe-bearing intermetallics. More recently, Atamanenko et al [18] investigated the grain refining effect of exogenous oxides combined with ultrasonic treatment in pure Al (99.95%Al), and attributed the grain refinement to cavitation-induced heterogeneous nucleation through the activation of oxides. In addition, it has been demonstrated that, via the introduction of intensive melt shearing using the MCAST process, naturally occurring oxides in liquid Mg-and Al-alloys can be harnessed to enhance heterogeneous nucleation for microstructural refinement in Mg and Al alloys [19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Mechanisms of enhanced heterogeneous nucleation during solidification in binary Al–Mg alloys

Li¹,

Wang²,

Fan³

2012

Acta Materialia

177

120

View full text Add to dashboard Cite

This paper investigates the mechanisms involved in the grain refinement of Al-Mg alloys through varying the Mg content and applying intensive melt shearing. It was found that the oxide formed in Al-Mg alloys under normal melting conditions is MgAl 2 O 4 , which displays an equiaxed and faceted morphology with {111} planes exposed as its natural surfaces. Depending on the Mg content, MgAl 2 O 4 particles exist either as oxide films in dilute Al-Mg alloys (Mg<1wt.%) or naturally dispersed discrete particles in more concentrated Al-Mg alloys (Mg>1wt.%). Such MgAl 2 O 4 particles can act as potent sites for nucleation of α-Al grains, which is evidenced by the well-defined cube-on-cube orientation relationship between MgAl 2 O 4 and α-Al. Enhanced heterogeneous nucleation in Al-Mg alloys can be attributed to the high potency of MgAl 2 O 4 particles with a lattice misfit of 1.4% and the increased number density of MgAl 2 O 4 particles due to either natural dispersion by the increased Mg content or forced dispersion through intensive melt shearing. It was also found that intensive melt shearing leads to significant grain refinement of dilute Al-Mg alloys by effective dispersion of the MgAl 2 O 4 particles entrapped in oxide films, but it has marginal effect on the grain refinement of concentrated Al-Mg alloys, where MgAl 2 O 4 particles have been naturally dispersed into individual particles by the increased Mg content.

show abstract

Criteria of Grain Refinement Induced by Ultrasonic Melt Treatment of Aluminum Alloys Containing Zr and Ti

Cited by 237 publications

References 20 publications

Influence of ultrasonic melt treatment on the formation of primary intermetallics and related grain refinement in aluminum alloys

Influence of ultrasonic melt treatment on the formation of primary intermetallics and related grain refinement in aluminum alloys

In Situ Synchrotron X-ray Study of Ultrasound Cavitation and Its Effect on Solidification Microstructures

Mechanisms of enhanced heterogeneous nucleation during solidification in binary Al–Mg alloys

Contact Info

Product

Resources

About