Effect of Rare Earth Metals on the Microstructure of Al-Si Based Alloys

Alkahtani, Saleh A.; Elgallad, E. M.; Tash, Mahmoud M.; Samuel, A. M.; Samuel, F. H.

doi:10.3390/ma9010045

Cited by 46 publications

(18 citation statements)

References 19 publications

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“…Figures 3 and 4 demonstrate the e ect of adding a relatively large amount of RE metals (without or with 0.15%Ti) to both base alloys. Based on these gures, it is clear that these additions resulted in As reported previously by the present authors [3,17], the observed depression in the eutectic temperature due to addition of RE metals is not necessarily related to modi cation of the eutectic Si particles as shown in Figure 5. It should be mentioned that only La revealed partial modi cation but was not as e ective a modi er as Sr in the Sr-treated alloys.…”

Section: Resultssupporting

confidence: 83%

Rare Earth Metal‐Based Intermetallics Formation in Al–Cu–Mg and Al–Si–Cu–Mg Alloys: A Metallographic Study

Samuel

Elgallad

Mahmoud

et al. 2018

Advances in Materials Science and Engineering

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This study was conducted on Al–Cu–Mg and Al–Si–Cu–Mg alloys containing either 5%La or 5%Ce. Two levels of Ti addition were examined, i.e., 0.05% and 0.15%. Thermal analysis was the only technique used to obtain castings, from which samples were then sectioned for metallographic examination. Based on the results obtained, the following points may be highlighted. Addition of a fairly large amount of RE metals (La or Ce) leads to the appearance of several peaks in the solidification curve between the precipitation of the primary α-Al phase and the (Al–Al2Cu) eutectic reaction. Although a significant drop in the eutectic temperature is caused by the addition of 5%La or Ce, the corresponding modification of the eutectic Si is marginal. Two main types of intermetallics were documented: a gray phase in the form of sludge with a fixed composition and a white phase in the shape of thin platelets. Due to the high affinity of RE to react with Si, Fe, and Cu, several compositions were obtained explaining the observed multiple peaks in the solidification curve. Judging by the morphology of the gray phase, it is assumed that this phase is precipitated in the liquid state and acts as a nucleation site for the white phase. Lanthanum and Ce can substitute each other.

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Section: Resultssupporting

confidence: 83%

Rare Earth Metal‐Based Intermetallics Formation in Al–Cu–Mg and Al–Si–Cu–Mg Alloys: A Metallographic Study

Samuel

Elgallad

Mahmoud

et al. 2018

Advances in Materials Science and Engineering

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“…There are examples with an application of mischmetal and individual elements with positive effects, no effects [89], and detrimental influence on properties of aluminum alloys [90]. Rare earth elements such as La, Ce, Nd, and Y were tested with the Al−Si matrix [91]; Er with Al−Mg, Al−Zn−Mg, Al−Zn−Mg−Cu, Al−Li, and Al−Cu grades [92]; or Sm with Al−Si−Cu grades [93]. Among rare earths, cerium and scandium are of particular interest for aluminum alloying, as emphasized in [94][95][96].…”

Section: Rare Earth Metals In Aluminum Alloysmentioning

confidence: 99%

Thermal Stability of Aluminum Alloys

Czerwiński

2020

Materials

112

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Thermal stability, determining the material ability of retaining its properties at required temperatures over extended service time, is becoming the next frontier for aluminum alloys. Its improvement would substantially expand their range of structural applications, especially in automotive and aerospace industries. This report explains the fundamentals of thermal stability; definitions, the properties involved; and the deterioration indicators during thermal/thermomechanical exposures, including an impact of accidental fire, and testing techniques. For individual classes of alloys, efforts aimed at identifying factors stabilizing their microstructure at service temperatures are described. Particular attention is paid to attempts of increasing the current upper service limit of high-temperature grades. In addition to alloying aluminum with a variety of elements to create the thermally stable microstructure, in particular, transition and rare-earth metals, parallel efforts are explored through applying novel routes of alloy processing, such as rapid solidification, powder metallurgy and additive manufacturing, engineering alloys in a liquid state prior to casting, and post-casting treatments. The goal is to overcome the present barriers and to develop novel aluminum alloys with superior properties that are stable across the temperature and time space, required by modern designs.

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“…In addition, some researchers have studied the interaction between rare earth elements and commercial modifier Sr in Al melts. Alkahtani et al [27] studied the effects of La and Ce additions on the structure and properties of an A356 alloy containing Sr. The experimental results showed that La and Ce tended to react with Sr and resulted in fading of the modification effect of the Sr.…”

Section: Introductionmentioning

confidence: 99%

Synergistic Effect of Nd and Ga on the Microstructure and Mechanical Properties of ER4047 Alloy Wires

Xue

Tao

et al. 2019

Metals

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The synergistic effects of Nd and Ga on the microstructure and mechanical properties of ER4047 alloy wires and the resulting MIG(Melt inert-gas welding) joints were investigated. Experimental results show that the hydrogen content in the liquid and solid alloy decreases rapidly and then increases slowly with the addition of Nd in the range of 0–0.8 wt.%. Under the same conditions, the hydrogen content ratio in the solid and liquid is between 1.9 and 2.1. After adding 0.08–0.2 wt.% Nd, the α-Al dendrites and eutectic Si phases in the ER4047 alloys are refined and modified, respectively; the quality index of the cast rod increases and the weld percent porosity of the MIG joint significantly decreases. However, when 0.8 wt.% Nd is added, although the size of the eutectic Si phase reaches a minimum value, a large number of coarse needle-like Nd-rich phases precipitate in the structure. Moreover, Ga inhibits the precipitation of the Nd-rich phases, thus improving the mechanical properties, especially the elongation of the cast rod. When 0.2 wt.% Nd and 0.05 wt.% Ga are added into the alloy wire, the porosity of the MIG joint reaches the lowest value herein, and the tensile strength and face/back bending angles reach their maximum values.

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Effect of Rare Earth Metals on the Microstructure of Al-Si Based Alloys

Cited by 46 publications

References 19 publications

Rare Earth Metal‐Based Intermetallics Formation in Al–Cu–Mg and Al–Si–Cu–Mg Alloys: A Metallographic Study

Rare Earth Metal‐Based Intermetallics Formation in Al–Cu–Mg and Al–Si–Cu–Mg Alloys: A Metallographic Study

Thermal Stability of Aluminum Alloys

Synergistic Effect of Nd and Ga on the Microstructure and Mechanical Properties of ER4047 Alloy Wires

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