The crystal growth of silicon in Al-Si alloys

Kobayashi, Keinosuke; Hogan, L.M.

doi:10.1007/bf01112278

Cited by 174 publications

(56 citation statements)

References 18 publications

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“…Na and Sr modifications of AlSi alloys have been extensively studied and numerous theories are proposed to explain the underlying phenomena [2][3][4][5][6][7][8][9][10][11][12]. In general, two approaches to explain the structural modification can be distinguished: the influence of the modifier on nucleation [13][14][15][16] and at the growth front of the eutectic phase [2][3][4][5][6][7][8]10].…”

Section: Introductionmentioning

confidence: 99%

“…In general, two approaches to explain the structural modification can be distinguished: the influence of the modifier on nucleation [13][14][15][16] and at the growth front of the eutectic phase [2][3][4][5][6][7][8]10]. The most well accepted hypotheses dealing with eutectic growth claim a Si growth restriction through the accumulation and adsorption of the modifier at the solid-liquid front.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of segregations formed in unmodified and Sr-modified Al–Si alloys studied by atom probe tomography and transmission electron microscopy

Barrirero

Engstler

Ghafoor

et al. 2014

Journal of Alloys and Compounds

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Comparison of segregations formed in unmodified and Sr-modified Al-Si alloys studied by atom probe tomography and transmission electron microscopy, 2014, Journal of Alloys and Compounds, (611) AbstractThe mechanical properties of Al-7 wt.% Si can be enhanced by structural modifications of its eutectic phase. Addition of low concentrations of certain elements, in this case 150 wt-ppm Sr, is enough to cause a transition from a coarse plate-like Si structure to a finer coralline one. To fully understand the operating mechanism of this modification, the composition of the eutectic Si phase in unmodified and Sr-modified alloys was analysed and compared by Atom Probe Tomography and (Scanning) Transmission Electron Microscopy. The unmodified alloy showed nanometre sized Al-segregations decorating defects, while the Sr-modified sample presented three types of Al-Sr segregations: (1) rod-like segregations that promote smoothening of the Al-Si boundaries in the eutectic phase, (2) particle-like segregations comparable to the ones seen in the unmodified alloy, and (3) planar segregations favouring the formation of twin boundaries. Al and Sr solubilities in Si after solidification were determined to be 430 ± 160 at-ppm and 40 ± 10 at-ppm, respectively. Sr predominantly segregates to the Si phase confirming its importance in the modification of the eutectic growth.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Comparison of segregations formed in unmodified and Sr-modified Al–Si alloys studied by atom probe tomography and transmission electron microscopy

Barrirero

Engstler

Ghafoor

et al. 2014

Journal of Alloys and Compounds

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“…[1] The discovery prompted many studies to examine the effect of the addition of alkali and alkaline earth metals [2][3][4][5][6][7][8][9] on Si nucleation and growth. From this work, it is now believed that nucleation is the dominant influencing factor in the modification process.…”

Section: Introductionmentioning

confidence: 99%

Study of Heterogeneous Nucleation of Eutectic Si in High-Purity Al-Si Alloys with Sr Addition

Zarif

McKay

Schumacher

2010

Metall Mater Trans A

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Al-5 wt pct Si master-alloys with controlled Sr and/or P addition/s were produced using super purity Al 99.99 wt pct and Si 99.999 wt pct materials in an arc melter. The master-alloy was melt-spun resulting in the production of thin ribbons. The Al matrix of the ribbons contained entrained Al-Si eutectic droplets that were subsequently investigated. Differential scanning calorimetry, thermodynamic calculations, and transmission electron microscopy techniques were employed to examine the effect of the Sr and P additions on eutectic undercoolings and nucleation phenomenon. Results indicate that, unlike P, Sr does not promote nucleation. Increasing Sr additions depressed the eutectic nucleation temperature. This may be a result of the formation of a Sr phase that could consume or detrimentally affect potent AlP nucleation sites.

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“…The effects of Na and Sr on the morphological modification have often been considered indistinctively [13][14][15]. Both elements produce multiplication of twins and lattice defects in the Si phase, as well as the same coralline-like eutectic microstructure.…”

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confidence: 99%