Grain refinement of aluminum alloys: Part I. the nucleant and solute paradigms—a review of the literature

Easton, Mark; StJohn, David H.

doi:10.1007/s11661-999-0098-5

Cited by 640 publications

(337 citation statements)

References 37 publications

Supporting

Mentioning

322

Contrasting

Unclassified

Order By: Relevance

“…So far there is no consensus on the detailed mechanisms of grain refinement [4,5]. Greer and co-workers developed the free growth model to describe the physical mechanism behind the low efficiency of commercial grain refiners based on the Al-Ti-B system [6,7].…”

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

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

show abstract

“…However, even if an extensive literature exists on the subject, the influence of the Si content on the refining effect and the role of Ti remain not clear. [1][2][3][4][5][6][7][8] Whatever the exact mechanism involved in grain refinement of Al-Si casting alloys by Ti containing master alloys, it is obvious that a better knowledge of the thermodynamics of the Al-Si-Ti system is required to elucidate this mechanism.…”

Section: Introductionmentioning

confidence: 99%

On the Liquid/Solid Phase Equilibria in the Al-Rich Corner of the Al-Si-Ti Ternary System

Dezellus

Gardiola

Andrieux

et al. 2014

J. Phase Equilib. Diffus.

View full text Add to dashboard Cite

The nature of liquid-solid phase equilibria in the Al-rich corner of the Al-Si-Ti system are determined by drawing three isothermal sections at 620, 680 and 727°C. The solubility of Ti in Al-Si liquids is determined for four different compositions (0, 9, 13 and 18 at.%Si) at temperature below 800°C. Combination of the two sets of experimental results leads to an attempt of liquidus projection. The primary crystallization surface of Al 3 Ti is found to extend up to 9.5 at.%Si in the liquid phase at 620°C and 11 at.%Si at 727°C. The solubility of Ti is found to be not significantly dependent on the Si content of the liquid. From DSC measurements and deduction on microstructure, the last invariant reaction of the solidification path is found to be quasi-peritectic: L

show abstract

“…The cast samples were ground using SiC paper (400 to 2500 grid size) and polished using OPS. For identification of grain size, polished samples were anodized using 4 pct HBF 4 solution for~1 minutes at 20 VDC and analyzed in polarized light in an optical microscope (Zeiss Axioscope). The microstructure of the master alloy was investigated using optical microscopy (OM) (Zeiss Axioscope) and scanning electron microscopy (SEM) (Zeiss Supra 35VP), and phase identification was performed using X-ray diffraction (XRD) (Bruker D8 Advance) and energy-dispersive spectroscopy (EDS) (EDAX).…”

Section: Methodsmentioning

confidence: 99%

“…[1][2][3][4][5] From the various grain refinement techniques, the most common practice is the addition of specialized master alloys containing potent nucleation substrates (TiB 2 , TiC, AlB 2 ), primary intermetallics (Al 3 Ti, Al 3 Nb, etc. ), and/or growth-restricting alloying elements (Ti, V, Nb, etc.).…”

Section: Introductionmentioning

confidence: 99%

Potential of an Al-Ti-MgAl2O4 Master Alloy and Ultrasonic Cavitation in the Grain Refinement of a Cast Aluminum Alloy

Sreekumar

Babu

Eskin

2016

Metall Mater Trans B

View full text Add to dashboard Cite

A new grain refining master alloy containing MgAl 2 O 4 and Ti was synthesized by in situ reaction of TiO 2 particles in an Al-Mg melt. MgAl 2 O 4 particles formed were distributed in the melt by ultrasonic cavitation processing. The obtained master alloy showed considerable (50 pct) grain refining ability in a commercial A357-type Al-Si alloy. Ultrasonication contributed further to 25 pct in the grain refinement. In comparison with a commercial Al-5 pct Ti-1 pct B master alloy, the efficiency of the new master alloy is less at a lower addition rate. Nevertheless, both master alloys performed similarly at higher additions. The strength and ductility of the inoculated and ultrasonicated alloy showed at least a 10 pct and a 50 pct increase, respectively, as compared with non-grain-refined alloy and a similar mechanical performance in comparison with the alloy inoculated with Al-5 pct Ti-1 pct B master alloy.

show abstract

Grain refinement of aluminum alloys: Part I. the nucleant and solute paradigms—a review of the literature

Cited by 640 publications

References 37 publications

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

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

On the Liquid/Solid Phase Equilibria in the Al-Rich Corner of the Al-Si-Ti Ternary System

Potential of an Al-Ti-MgAl2O4 Master Alloy and Ultrasonic Cavitation in the Grain Refinement of a Cast Aluminum Alloy

Contact Info

Product

Resources

About