The effect of cooling rate on the morphology of primary Al3Sc intermetallic particles in Al–Sc alloys

Hyde, K; Norman, A.F.; Prangnell, P.B.

doi:10.1016/s1359-6454(01)00050-7

Cited by 181 publications

(67 citation statements)

References 15 publications

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“…Precipitation can also release compressive stress. 12,17) The results obtained herein indicate that Al-Sc and Al-Nd alloy films have excellent resistance. Both can be used to make TFT-LCD interconnections.…”

Section: )mentioning

confidence: 62%

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Characteristics of Sputtered Al-Sc and Al-Nd Alloy Thin Films for use in Liquid Crystal Display

Chen

Huang

2005

Mater. Trans.

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The interconnections among thin film transistor liquid crystal displays (TFT-LCDs) are laid on the films, made by the spotted coating method. This work studies the effect of heat-treatment, at temperatures from 523 K to 673 K, on the microstructure and physical properties of the deposited alloy thin films. The experimental results imply that, following heat treatment, the roughness of the aluminum-scandium (Al-Sc) alloy film is less than that of the aluminum-neodymium (Al-Nd) alloy, and the hillocks of the Al-Sc alloy film are lower. Accordingly, components are predicted to fail less often. The resistivity of the Al-Sc thin film is less than that of the Al-Nd thin film before it is thermally treated. Heat treatment reduces the resistivity of both, even though the reduced resistivity of Al-Nd exceeds the resistivity of the Al-Sc alloy film. Restated, the resistivity of the thermally stable Al-Sc thin film exceeds that of the Al-Nd thin film. Experimental results imply that the Al-Sc alloy is the more effective for making the driving circuit wires in the TFT-LCDs.

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Section: )mentioning

confidence: 62%

“…The L1 2 Al 3 Sc precipitates suppress recrystallization. 16,17) The Al 3 Sc phase has an ordered L1 2 crystal structure and a small lattice mismatch with an Al content of only 1.5%.…”

Section: Microstructures Of Filmsmentioning

confidence: 99%

Characteristics of Sputtered Al-Sc and Al-Nd Alloy Thin Films for use in Liquid Crystal Display

Chen

Huang

2005

Mater. Trans.

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“…due to the similarity of its crystal structure with that of the aluminum. 146 In this study, the Sc content is 0.5 wt%, thus the formation of the primary AlsSc intermetallic compound is not expected to take place during solidification. This was confirmed by the fact that primary particles of AI3SC phase were difficult to find in the alloys under investigation.…”

Section: 212 Ai 3 Sc Intel-metallic Phasementioning

confidence: 84%

“…76 ' 146 This compound has a great capacity for acting as a nucleant in a-A! due to the similarity of its crystal structure with that of the aluminum.…”

Section: 212 Ai 3 Sc Intel-metallic Phasementioning

confidence: 99%

Influence of zirconium and scandium on the microstructure, tensile properties, and hot-tearing susceptibility of Al-2WT%Cu-based alloys /

Nabawy¹

2010

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In the second alloy category, seventeen alloy compositions were prepared, using different additions of Zr, Sc, Ti-B, Sr, Ag, and Si These alloys were further divided into four groups, namely, the Zr-Ti, Zr-Sr, Zr-Sc, and Si alloy groups. Tensile test bars (cooling rate 7°C/s) prepared from these alloys were solutionized for 8h at 490°C then age-hardened at temperatures of 180°C and 220°C for aging times of 2, 4, 6, 10,16, 24, and 48h, and 0.5,1, 1.5, 2, 4, 6, 10, 16, 24, and 48h, respectively. It was observed that combined additions of Zr-Ti Zr-Sr, or Zr-Sc refined the grain size of the base alloy considerably, from 219 um to 104-46 urn, since these elements form primary trialuminide intermetallics including Al3(Sci-x Zr x ), Al3(Sci-x -yZr x Tiy), and AlaZr which act as nucleation sites for o-Al grains, thereby producing fine non-dendritic structures. The refined non-dendritic morphology produced by the combined additions of Zr-Ti Zr-Sr, or Zr-Sc caused a reduction of about 65% in the amount of the AliCu phase in the base alloy, and a reduction in porosity of about 50%. The addition of 2 wt% Si also produced the same reduction levels in the amount of AfeCu and porosity, brought about by the increase in the Al-Si eutectic content. Age-hardening peaks were observed after aging for lOh and 24h at 180°C, and after aging for Ih and 2h at 220°C. The Zr-Sr and Zr-Ti alloy groups displayed the highest level of improvement in the tensile properties of the Al-2wt%Cu base alloy followed by the Zr-Sc and Si alloy groups, in that order. The 0.02wt%Sr-0.7wt%Zr containing alloy produced the highest ultimate tensile and yield strength values of 383 MPa and 326 MPa, respectively, after 4h of aging at 180°C. The strength of the base alloy increased in the Zr-Ti alloy group with an increase in Zr content from 0.15wt% to 0.7wt% after aging at 180°C for lOh. This increase may be variously attributed to Al$Zr and Al3(Zri. x Ti x ) dispersoids acting as heterogeneous nucleation sites for age-hardening phases; to the modifying action of Zr on the S' (AfeCuMg) phase; and to the action of Zr-Ti in producing a refined non-dendritic grain structure. Combined additions of Zr-Sr and Sr-Ti displayed the best elongation levels of all the alloys investigated, as witnessed by the 0.02wt%Sr-0.15wt%Ti-containing alloy and, 0.02wt%Sr-0.7wt%Zr-containing alloy. These improved levels may be the result of the modifying effects of Sr on o-Fe particles, as well as of the roles of Zr and Ti in producing a fine non-dendritic os-Al structure. The 0.02wt%Sr-0.15wt%Ti-containing alloy displayed the highest resistance to softening during aging at 220°C because of the respective modifying and refining effects of Sr and Ti on the microstructure.

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“…The primary Al 3 Sc precipitates can easily be identified in unetched metallographic cross sections by their typical square structure [12]. The micrograph of the direct chill cast material shows primary Al 3 Sc precipitates with a side length between 20 and 30 lm ( Figure 6c).…”

Section: Microstructurementioning

confidence: 98%

Spray formed and rolled aluminium‐magnesium‐scandium alloys with high scandium content

Herding

Keßler²,

Zoch

2007

Materialwissenschaft Werkst

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Aluminium-magnesium-scandium alloys offer good weldability, high corrosion resistance, high thermal stability and the potential for high strength by precipitation hardening. A problem of aluminium-scandium alloys is the low solubility of about 0.3 mass-% scandium when using conventional casting methods. The solution of scandium can be raised by higher cooling rates during solidification. This was realised by spray forming of Al-4.5Mg-0.7Sc alloys as flat deposits. Further cooling rates after solidification should also be high to prevent coarse precipitation of secondary Al 3 Sc. Therefore a cooling device was designed for the spray formed flat deposits. The flat deposits were rolled at elevated temperatures to close the porosity from spray forming. Microstructures, aging behaviour and tensile properties of the rolled sheets were investigated. Strength enhancements of about 100 MPa compared to conventional Al-Mg-Sc alloys were achieved.Keywords: Al-Mg-Sc alloys, spray forming, rolling, microstructure, tensile properties Aluminium-Magnesium-Scandium-Legierungen zeichnen sich durch gute Schweißeignung, hohe Korrosionsbeständigkeit, hohe thermische Stabilität und ein hohes Potenzial zur Ausscheidungshärtung aus. Problematisch ist die relativ geringe Löslichkeit von 0,3 Masse-% Scandium in Aluminium bei konventionellen Gieß-verfahren. Die Löslichkeit von Scandium kann durch höhere Abkühlgeschwindigkeiten bei der Erstarrung gesteigert werden. Dies wurde mittels Sprühkompaktieren einer AlMg4,5Sc0,7-Legierung zu Flachprodukten realisiert. Auch nach der Erstarrung muss die Abkühlgeschwindigkeit ausreichend hoch sein, um grobe sekundäre Al 3 Sc-Ausscheidungen zu unterdrücken. Dies wurde mittels einer Kühlvorrichtung für die sprühkompaktierten Flachprodukte realisiert. Anschließend wurden die Flachprodukte warmgewalzt, um die Porosität zu schließen. Gefüge, Auslagerungsverhalten und Kenngrößen des Zugversuchs der gewalzten Bleche wurden untersucht. Die Festigkeit konnte um ca. 100 MPa gegenüber konventionellen Al-Mg-Sc-Legierungen gesteigert werden.

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The effect of cooling rate on the morphology of primary Al3Sc intermetallic particles in Al–Sc alloys

Cited by 181 publications

References 15 publications

Characteristics of Sputtered Al-Sc and Al-Nd Alloy Thin Films for use in Liquid Crystal Display

Characteristics of Sputtered Al-Sc and Al-Nd Alloy Thin Films for use in Liquid Crystal Display

Influence of zirconium and scandium on the microstructure, tensile properties, and hot-tearing susceptibility of Al-2WT%Cu-based alloys /

Spray formed and rolled aluminium‐magnesium‐scandium alloys with high scandium content

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