Effects of La intermetallics on the structure and tensile properties of thin section gravity die-cast A357 Al alloy

Pourbahari, B.; Emamy, M.

doi:10.1016/j.matdes.2016.01.039

Cited by 54 publications

(15 citation statements)

References 34 publications

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“…If the amount of rare earth added to the alloy exceeds a certain value, the rare earth element will be enriched at the front of the solidification interface (it is shown in Figure 5) and prevent the diffusion of other alloying elements into the solid phase, then reduce the solid solubility of alloy elements in matrix α-Al, make the number of eutectic increase, cause segregation and reunion, hinder the refinement effect, and make the organization begin to deteriorate. Furthermore, Pourbahari [32] reported that, at a higher La levels, the new La-rich intermetallic (AlSiLa intermetallic) slows the growth rate of the α-Al primary phase. It reduced the strengthening phase of the alloy.…”

Section: Microstructure and Microhardnessmentioning

confidence: 99%

Effect of the Addition of Rare Earth Element La on the Tribological Behaviour of AlSi5Cu1Mg Alloy

2018

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Abstract:The effects of 0, 0.3, 0.6 and 0.9 wt % modifier La on the dry sliding wear behaviours of AlSi5Cu1Mg alloy were investigated under different friction conditions (normal loads, sliding velocities) by using pin-on-disc configuration. The microhardness of the alloys was tested, and it was found that the microhardness of the alloys was improved by the La addition. The AlSi5Cu1Mg + 0.6 wt % La alloy exhibited the smallest grain size and maximum microhardness. The wear mechanism analysis of the worn surface was done, which drew support from a scanning electron microscope (SEM) that was equipped with an energy dispersive spectrometer. The results showed that AlSi5Cu1Mg + 0.6 wt % La alloy exhibited the best wear resistance, which was mainly due to the modified grain and microhardness. At the sliding velocity of 0.19 m/s, the adhesive wear became the main wear mechanism with the increase of the load because of the rupture of the oxide layer on the friction surface. Under the load of 3.8 MPa, the abrasive wear became slight as the sliding velocity increasing, due to the recrystallization phenomenon that happened in the frictional surface.

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Section: Microstructure and Microhardnessmentioning

confidence: 99%

Effect of the Addition of Rare Earth Element La on the Tribological Behaviour of AlSi5Cu1Mg Alloy

2018

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“…Continue increasing solution time to 3 h (Figure c), more Sr element diffuse into α ‐Al and the distribution is more homogeneous. As for La element, it distributes uniformly and changes little under all of the conditions, because La and La‐containing phases are considered as the nucleation cores of α ‐Al . In addition, as a type of surface active agent, La can promotes the diffusion of Mg and Si in the matrix, and decreases conglomeration of impurities in unit area and grain boundaries .…”

Section: Discussionmentioning

confidence: 99%

Effect of Solution Treatment on Microstructure and Mechanical Properties of A356.2 Aluminum Alloy Treated With Al–Sr–La Master Alloy

Ding

Miao

et al. 2018

Adv Eng Mater

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Morphology and mechanical performances of A356.2 aluminum alloy under solution treatment are important for its application, specifically for alloys treated with newly-developed combined refiner-modifier. In this work, effect of solution temperature, solution time, and quenching medium temperature on the microstructure and mechanical properties of A356.2 aluminum alloy treated with Al-6Sr-7La master alloy are investigated. Results show that eutectic silicon undergo disintegration, spheroidization, and coarsening stages with solution temperature increasing. Volume fraction of eutectic silicon decreases gradually with solution temperature increasing from 495 to 550 C, while secondary dendritic arm spacing (SDAS) increases gradually during this process. At the solution temperature of 540 C, aspect ratio of eutectic silicon approached to about 1.3 and eutectic silicon undergo spheroidization and coarsening stages with extension of solution time. Moreover, SDAS increases with increasing of quenching medium temperature, which affects the ultimate tensile strength (UTS), yield strength (YS), and elongation (EL) of the alloy, especially for tensile strength and elongation. Optimal solution parameters for A356.2 aluminum alloy treated with Al-6Sr-7La are obtained and the reasons are discussed.

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“…The other elements provided only a minor refinement of the plate-like silicon morphology. Pourbahari et al [12] studied the effects of La addition and heat treatment on the microstructure and tensile properties of A357 aluminum alloy. Their results showed that the addition of La obviously reduced the size and area of eutectic silicon particles after heat treatment.…”

Section: Advances In Materials Science and Engineeringmentioning

confidence: 99%

Effects of La and Ce Addition on the Modification of Al-Si Based Alloys

Elgallad

Doty

Alkahtani

et al. 2016

Advances in Materials Science and Engineering

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This study focuses on the effects of the addition of rare earth metals (mainly lanthanum and cerium) on the eutectic Si characteristics in Al-Si based alloys. Based on the solidification curves and microstructural examination of the corresponding alloys, it was found that addition of La or Ce increases the alloy melting temperature and the Al-Si eutectic temperature, with an Al-Si recalescence of 2-3°C, and the appearance of post-α-Al peaks attributed to precipitation of rare earth intermetallics. Addition of La or Ce to Al-(7–13)% Si causes only partial modification of the eutectic Si particles. Lanthanum has a high affinity to react with Sr, which weakens the modification efficiency of the latter. Cerium, however, has a high affinity for Ti, forming a large amount of sludge. Due to the large difference in the length of the eutectic Si particles in the same sample, the normal use of standard deviation in this case is meaningless.

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Effects of La intermetallics on the structure and tensile properties of thin section gravity die-cast A357 Al alloy

Cited by 54 publications

References 34 publications

Effect of the Addition of Rare Earth Element La on the Tribological Behaviour of AlSi5Cu1Mg Alloy

Effect of the Addition of Rare Earth Element La on the Tribological Behaviour of AlSi5Cu1Mg Alloy

Effect of Solution Treatment on Microstructure and Mechanical Properties of A356.2 Aluminum Alloy Treated With Al–Sr–La Master Alloy

Effects of La and Ce Addition on the Modification of Al-Si Based Alloys

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