Microstructural characterisation of Al–Si cast alloys containing rare earth additions

Elgallad, E. M.; Ibrahim, M. F.; Doty, H. W.; Samuel, F. H.

doi:10.1080/14786435.2018.1435917

Cited by 30 publications

(14 citation statements)

References 27 publications

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“…The tendency to form a network of Al11(Ce, La)3 also appears to be less as the smaller Al11(Ce, La)3 plates appears to be lesser, with the formation of the large primary precipitated Al11(Ce, La)3 plates, Figure 6d. While according to the report, the addition of combined (Ce and La) did not modify the A356 silicon morphology, even increase the coarseness of silicon particles [35]. The quantitative microstructural characterization is collected in Table 3.…”

Section: Microstructural Characteristicsmentioning

confidence: 82%

The Influence of La and Ce on Microstructure and Mechanical Properties of an Al-Si-Cu-Mg-Fe Alloy at High Temperature

Jarfors

Zheng

et al. 2021

Metals

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The effect of lanthanum (La)+cerium (Ce) addition on the high-temperature strength of an aluminum (Al)–silicon (Si)–copper (Cu)–magnesium (Mg)–iron (Fe)–manganese (Mn) alloy was investigated. A great number of plate-like intermetallics, Al11(Ce, La)3- and blocky α-Al15(Fe, Mn)3Si2-precipitates, were observed. The results showed that the high-temperature mechanical properties depended strongly on the amount and morphology of the intermetallic phases formed. The precipitated tiny Al11(Ce, La)3 and α-Al15(Fe, Mn)3Si2 both contributed to the high-temperature mechanical properties, especially at 300 °C and 400 °C. The formation of coarse plate-like Al11(Ce, La)3, at the highest (Ce-La) additions, reduced the mechanical properties at (≤300) ℃ and improved the properties at 400 ℃. Analysis of the strengthening mechanisms revealed that the load-bearing mechanism was the main contributing mechanism with no contribution from thermal-expansion mismatch effects. Strain hardening had a minor contribution to the tensile strength at high-temperature.

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Section: Microstructural Characteristicsmentioning

confidence: 82%

The Influence of La and Ce on Microstructure and Mechanical Properties of an Al-Si-Cu-Mg-Fe Alloy at High Temperature

Jarfors

Zheng

et al. 2021

Metals

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“…Due to Ce-Ti interaction, the grain refining effectiveness was reduced in the 3C and 4C alloys, as shown in Figure (c, f). Microstructural characterization of Al-Si cast alloys containing rare earth additions was performed by Elgallad et al [93]. The main findings of this study were that the addition of La and/or Ce resulted in the formation of a whitecoloured Al-Si-La/Ce/(La,Ce) phase in both A356 and A413 alloys.…”

Section: Parameter Descriptionmentioning

confidence: 64%

“…The mean length of the needle-like phase dropped from 364 to 55.3 μm, while the SDAS decreased from $22 to 9.7 μm, i.e., by 84.5% and 55.8%, respectively. [93].…”

Section: Parameter Descriptionmentioning

confidence: 99%

Applications of Rare Earth Metals in Al-Si Cast Alloys

Mahmoud¹,

Zedan²,

Samuel³

et al. 2021

Advances in High-Entropy Alloys - Materials Research, Exotic Properties and Applications

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The present article reviews a large number of research publications on the effect of mischmetal (MM), rare earth metals (RE), La or Ce, and combinations of La + Ce on the performance of Al-Si cast alloys mainly 319, 356, 380, 413, and 390 alloys. Most of these articles focused on the use of rare earth metals as a substitute for strontium (Sr) as a eutectic silicon (Si) modifier if added in low percentage (< 1 wt.%) to avoid precipitation of a significant amount of insoluble intermetallics and hence poor mechanical properties. Other points that were considered were the affinity of RE to react with Sr., reducing its effectiveness as modifier, as well as the grain refining efficiency of the added RE in any form. None of these articles mentioned the exact composition of the RE used and percentage of tramp elements inherited from the parent ore. Using high purity La or Ce proved to have no effect on the Si shape, size or distribution, in particular at low solidification rates (thick sections). However, regardless the source of the RE, its addition to Sr-modified alloys reduced the modification effect. As for grain refining, apparently a high percentage of RE (> 1 wt.%) is required to achieve a noticeable reduction in grain size, however at the cost of alloy brittleness.

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“…The rare earth elements have special activity compared with chemical modifiers [8] and have a good effect on the secondary dendrite arm spacing (SDAS), grain size refinement, eutectic Si modifiers, and hydrogen removal, as a consequence the tensile properties of the alloy are improved. Furthermore, rare earth elements are an excellent modifier for cast aluminum alloys because of their relatively long-lasting properties and remelting stability [9,10].…”

Section: Introductionmentioning

confidence: 99%

Effect of Ce Addition and Heat Treatment on Microstructure Evolution and Tensile Properties of Industrial A357 Cast Alloy

Wang

Liu

Zheng

et al. 2020

Metals

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The effects of adding different Ce contents (0–0.32 wt.%) on the microstructure, mechanical properties, and fracture morphology of industrial A357 cast alloy in as-cast and T6 heat treatment were studied. The main purpose of this study is to improve the microstructure stability and tensile properties of industrial A357 cast alloy. The microstructural analyses indicate that the addition of Ce causes refinement of the α-Al primary phase for the reason that the formation of intermetallic compounds containing (AlSiCeMg) elements enriches the front of the solid–liquid interface, which causes an increase in constitutional undercooling. Simultaneously, the addition of Ce also affected the characteristics of eutectic Si particles, which make its morphology change from acicular structures into fragmented and spheroidized. This is mainly due to the formation of Ce-rich precipitates during solidification, which increase the constitutional undercooling and suppress the nucleation of the eutectic Si particles, resulting in the change of eutectic Si characteristics. Moreover, the needle-like morphology of a Fe-containing intermetallic is transformed into α(AlSiFeCe) phase containing rare earth Ce when part of the Ce atoms entered β(Al5FeSi) phase compounds. The tensile properties of the modified alloys were improved in the as-cast and T6 heat treatment as a consequence of simultaneous refinement of both secondary dendrite arm spacing and grains and the improvement of eutectic Si particles and Fe-containing intermetallic morphology. The fracture surface of the modified alloy has more dimples than the unmodified alloy, which indicates that the main fracture pattern of the modified alloy is dimple fracture caused by the crack of eutectic Si particles. The optimal percentage of Ce in industrial A357 cast alloy was determined to be 0.16 wt.% according to the change of microstructures structure and mechanical properties. These experimental results provide a new basis for adding rare earth Ce to improve the performance of parts in the actual production of industrial A357 cast alloy.

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Microstructural characterisation of Al–Si cast alloys containing rare earth additions

Cited by 30 publications

References 27 publications

The Influence of La and Ce on Microstructure and Mechanical Properties of an Al-Si-Cu-Mg-Fe Alloy at High Temperature

The Influence of La and Ce on Microstructure and Mechanical Properties of an Al-Si-Cu-Mg-Fe Alloy at High Temperature

Applications of Rare Earth Metals in Al-Si Cast Alloys

Effect of Ce Addition and Heat Treatment on Microstructure Evolution and Tensile Properties of Industrial A357 Cast Alloy

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