Heterogeneously nucleated α-Al in amorphous aluminium alloys

Schumacher, Peter; Greer, A.L.

doi:10.1016/0921-5093(94)90559-2

Cited by 63 publications

(37 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Also mechanism of grain refinement by Al-Ti-B grain refiners has been explained by various analytical models and theories and verified experimentally [1][2][3][4][5][6][7]. It has been realized that peritectics often can effectively refine the grains of Al, e.g.…”

Section: Introductionmentioning

confidence: 99%

Grain Refinement Efficiency of a New Oxide-Containing Master Alloy for Aluminium Casting Alloys

Sreekumar

Babu

Eskin

et al. 2014

MSF

View full text Add to dashboard Cite

show abstract

Section: Introductionmentioning

confidence: 99%

Grain Refinement Efficiency of a New Oxide-Containing Master Alloy for Aluminium Casting Alloys

Sreekumar

Babu

Eskin

et al. 2014

MSF

View full text Add to dashboard Cite

show abstract

“…), and/or growth-restricting alloying elements (Ti, V, Nb, etc.). [6][7][8][9][10] In current industrial practice, Al-Ti-B (Al-Ti-TiB 2 ) and Al-Ti-C (Al-Ti-TiC) master alloys are the most common grain refiners used in cast and wrought Al alloys. [2,3] The grain refinement mechanisms as well as some technological issues related to Si or Zr poisoning of Al-Ti-B grain refiners are thoroughly scrutinized by theoretical models and experiments.…”

Section: Introductionmentioning

confidence: 99%

“…[11,12] Despite the commercial success of Al-Ti-B and Al-Ti-C grain refiners, some drawbacks are related to their application such as reduced performance in high-Sior Zr-containing alloys and agglomeration of borides in Al-Ti-B master alloys and a narrow process-parameter window for Al-Ti-C master alloys. [1,2,5,6,12] A search for new grain refining systems that may substitute that currently used is ongoing. In recent times, interest has grown on using oxides such as Al 2 O 3 , MgAl 2 O 4 , and MgO as nucleation substrates in Al.…”

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

“…The presence of solutes (e.g. Ti) enhances the TiB 2 grain refinement potency by tailoring the heterogeneous nucleation interface of TiB 2 [10]. To date, there is still a lack of atomic scale experimental investigations of the heterogeneous nucleation interface of TiB 2 under industrial solidification conditions (e.g.…”

mentioning

confidence: 99%

“…

Refinement of Al alloys by TiB 2 has been extensively studied in both industry and academia for several decades [1][2][3][4][5][6][7][8][9][10]. The presence of solutes (e.g.

…”

mentioning

confidence: 99%

The Heterogeneous Nucleation Sequence at the Interface of TiB₂ in Al Alloys

Hage

Ramasse

et al. 2017

Microsc Microanal

View full text Add to dashboard Cite

Refinement of Al alloys by TiB 2 has been extensively studied in both industry and academia for several decades [1][2][3][4][5][6][7][8][9][10]. The presence of solutes (e.g. Ti) enhances the TiB 2 grain refinement potency by tailoring the heterogeneous nucleation interface of TiB 2 [10]. To date, there is still a lack of atomic scale experimental investigations of the heterogeneous nucleation interface of TiB 2 under industrial solidification conditions (e.g. conventional die casting). In order to address these open issues, a combination of atomic scale high angle annular dark field (HAADF) imaging and electron energy loss spectroscopy (EELS) in the dedicated aberration corrected scanning transmission electron microscope (STEM) is used for the characterization of the heterogeneous nucleation interface of TiB 2 in Al alloys, with a special focus on the partitioning of non-interacting solute elements (e.g. Ti and Cu) to TiB 2 . Experiments were carried out on two distinct material systems in order to more accurately elucidate the multiple roles of Ti in Al alloys and to determine the dominant mechanism for grain refinement in Al alloys. Firstly, as a reference, the heterogeneous nucleation interface of TiB 2 in a commercial Al-Ti-B grain refiner (i.e. Al-5Ti-1B) was studied. Secondly, the grain refinement of Al-Cu based alloys with varying Ti content (but with identical growth restrictions to the reference case) was investigated. The heterogeneous nucleation interface of TiB 2 in Al-Cu based alloys was also studied. The effect of the solidification path (i.e. a peritectic reaction and a subsequent peritectic transformation) on the observed nucleation phenomena is also discussed. Figure 1 shows a significant partitioning of Ti to the surface of TiB 2 in the commercial grain refiner (Al5Ti-1B). During solidification, the presence of a Ti-rich monolayer is strongly dependent on the solidification path. This is because the Ti-rich monolayer can potentially be consumed by a peritectic reaction. Figure 2 shows that Ti partitioning is present together with a significant Cu-rich monolayer (most likely Al 2 Cu) on the surface of the TiB 2 particle, in an Al-Cu based alloy. The above discussed Ti and Cu rich monolayers were observed over the whole surface of the respective TiB 2 particles. A nucleation sequence on the basal plane of TiB 2 is proposed. Firstly, Al nucleation occurs on an Al 3 Ti monolayer. Secondly, the Al 3 Ti monolayer is preserved from the subsequent peritectic transformation by a surrounding eutectic reaction layer that forms Al 2 Cu on Al. Based on this nucleation sequence, the absence or presence of an Al 3 Ti monolayer on the basal plane of TiB 2 can be interpreted. The present work provides a clearer picture of the heterogeneous nucleation interface between TiB 2 and Al and demonstrates that an Al 3 Ti monolayer must be present if the grain refinement is growth-limited. Only then can growth restriction and concentration undercooling play their full part.

show abstract

Heterogeneously nucleated α-Al in amorphous aluminium alloys

Cited by 63 publications

References 2 publications

Grain Refinement Efficiency of a New Oxide-Containing Master Alloy for Aluminium Casting Alloys

Grain Refinement Efficiency of a New Oxide-Containing Master Alloy for Aluminium Casting Alloys

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

The Heterogeneous Nucleation Sequence at the Interface of TiB₂ in Al Alloys

Contact Info

Product

Resources

About

Heterogeneously nucleated α-Al in amorphous aluminium alloys

Cited by 63 publications

References 2 publications

Grain Refinement Efficiency of a New Oxide-Containing Master Alloy for Aluminium Casting Alloys

Grain Refinement Efficiency of a New Oxide-Containing Master Alloy for Aluminium Casting Alloys

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

The Heterogeneous Nucleation Sequence at the Interface of TiB2 in Al Alloys

Contact Info

Product

Resources

About

The Heterogeneous Nucleation Sequence at the Interface of TiB₂ in Al Alloys