Cluster-assisted nucleation of silicon phase in hypoeutectic Al–Si alloy with further inoculation

Zhang, Yong; Zheng, Hui; Liu, Yue; Shi, Lei; Xu, Rongfu; Tian, Xuelei

doi:10.1016/j.actamat.2014.01.061

Cited by 73 publications

(22 citation statements)

References 62 publications

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“…In the silicon matrix, there are two isolated nanoparticles with special crystal structures. The corresponding fast Fourier transforms (FFTs) of these nanoparticles reveal that they cannot be identified as any well-established crystals known in Al-Si-Fe alloy systems, and this agrees well with the nanoparticles earlier reported in Al-Si alloys inoculated with the (AlFeSi) clusters [11,12]. Therefore, it is reasonable to conclude that (AlFeSi) clusters developing in the melts play the dominant role in enhancing the nucleation of silicon phase.…”

Section: Resultssupporting

confidence: 77%

“…Due to the inherent covalent bonds in these clusters [20], these developed (AlFeSi) clusters can remain relatively stable against increased temperatures in the studied temperature and time range. Furthermore these (AlFeSi) clusters can trigger the segregation of aluminum and silicon atoms around them, which evolve into iron-poor precursors through the migration of iron atoms out [11]. These nanoparticles shown in Fig.…”

Section: Resultsmentioning

confidence: 97%

“…Even though extensive studies have focused on the iron-rich phases in Al-Si alloys [7][8][9][10], only few reports have concentrated on the beneficial effects of iron in Al-Si alloys. Recently, an iron-rich particle, b-Al 5 FeSi, was used as an inoculant and found to evolve into a kind of Mackay icosahedral (AlFeSi) clusters, and enhance the silicon phase nucleation [11,12]. Though the inoculating effect is pronounced, it still relies on exogenous addition, i.e., an Al-10Si-2Fe master alloy containing b-Al 5 FeSi.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Efficient use of iron impurity in Al–Si alloys

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Liu²,

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Section: Resultssupporting

confidence: 77%

Section: Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Efficient use of iron impurity in Al–Si alloys

Yong¹,

Liu²,

Shi³

et al. 2014

Journal of Alloys and Compounds

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“…To maintain the alloy strength at increased temperatures, a microstructure containing thermally stable and coarsening-resistant phases is needed [5]. The Al-Si alloys represent the most common grades used in casting applications [6,7]. Due to the presence of non-deformable and brittle eutectics or primary silicon phase, the hot workability of the AlSi alloys is rather limited [8].…”

Section: Introductionmentioning

confidence: 99%

Effect of Zr, V and Ti on hot compression behavior of the Al–Si cast alloy for powertrain applications

Shaha

Czerwiński

Kasprzak

et al. 2014

Journal of Alloys and Compounds

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“…However, this point is actually controversial, because some nanoscale particles (5 ~ 20 nm) have recently been found to act as nucleation sites [90]. On the other hand, significant grain refinement will not be expected if the particle diameter is too large, because the number density of particles decreases a lot.…”

Section: Geometrical Features Of Potent Nucleantsmentioning

confidence: 95%

Novel approach to grain refinement of cast Zn alloys

Liu¹

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Grain refinement through inoculation treatment is an important process in metal casting, because the refined grains introduce sound castability, enhance chemical and structural uniformity, improve the mechanical properties and increase the formability in the subsequent forming process.A number of effective grain refiners have already been well developed and practically used in light metals/alloys, such as Al and Mg alloys. As one of the most common engineering materials in use, cast Zn possesses many advantages, including energy-saving melting, casting soundness, good corrosion resistance and dimensional tolerance. In addition, the majority of Zn alloy components are wrought products, thus, the formability of the alloy is critical. However, Zn cast products are normally associated with coarse grains, which result in brittleness, low strength and poor formability. Hence, grain refinement of cast Zn alloys has been considered as an effective approach to increase the quality of Zn products at the lowest cost. However, there are few efficient grain refiners available for cast Zn due to the lack of research on grain refinement in this type of alloys.Based on the currently available grain refinement theories/models that were developed in Al and Mg alloys, four new grain refiners (master alloys), i.e. Zn-10wt.% Ag, Zn-18wt.% Cu, Zn-60wt.% Mg and Zn-6wt.% Al, were originally developed for cast Zn in this PhD project. Foundry test shows that all these four grain refiners can produce significant grain refinement in cast Zn.Furthermore, the grain refining mechanisms were also comprehensively investigated in terms of the three phase diagram related parameters, i.e. growth restriction factor (Q), supercooling parameter (P) and freezing range (∆T), and the crystallography of heterogeneous nucleation. It was found that no single factor can define the grain refining efficiency.The effect of grain refinement on tensile properties of cast Zn alloys was studied through specially-designed experiments. Two groups of Zn-Mg and Zn-Al alloys with fixed solute contents were prepared using different cooling rates to achieve various grain sizes, which enables to distinguish grain-refinement strengthening from solid-solution strengthening. Then, the Hall-Petch equations were determined in binary Zn-Mg and Zn-Al alloys, respectively. Through controlling the addition levels of Mg/Al in Zn melts, the different grain sizes of another two groups of binary cast Zn alloys (solidified at a fixed cooling rate) were also produced, in which both grain-refinement strengthening and solid-solution strengthening coexist. After extracting the grain-refinement strengthening component, the contribution of solid-solution strengthening to the yield strength was then mathematically quantified. Further, empirical relations, between yield strength, grain size, solute content and intrinsic friction, in different alloys were established. The experimental results indicate that the yield stress of all alloys was increased by > 50 MPa compared with the unr...

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Cluster-assisted nucleation of silicon phase in hypoeutectic Al–Si alloy with further inoculation

Cited by 73 publications

References 62 publications

Efficient use of iron impurity in Al–Si alloys

Efficient use of iron impurity in Al–Si alloys

Effect of Zr, V and Ti on hot compression behavior of the Al–Si cast alloy for powertrain applications

Novel approach to grain refinement of cast Zn alloys

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