An analytical model of irregular eutectic growth and its application to Fe-C

Magnin, P; Kurz, W.

doi:10.1016/0001-6160(87)90059-9

Cited by 149 publications

(69 citation statements)

References 9 publications

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“…The ternary eutectic microstructure is substantially more intricate and morphologically detailed than the typical binary irregular eutectic, where the facetted phase leads the eutectic reaction front and is interconnected via a massive semiplanar nonfacetted component. [1,7,8] As a result, the ternary eutectic mush becomes considerably deeper with liquid pockets that remain open until the Al-Al 2 Cu eutectic solidifies. In the G || g DS geometry, …”

Section: Resultsmentioning

confidence: 99%

“…Fisher and Kurz [1] made the first attempts at deriving a constitutive two-dimensional (2-D) model for irregular eutectic growth by an extension of the Jackson-Hunt model, [2] applying isothermal coupling conditions over local regions of the interface in order to bypass the difficulties of handling the dynamics of a nonisothermal front. Magnin and Kurz [7] generalized to a full nonisothermal treatment with a 2-D model that later was modified further by Guzik and Kopycin´ski. [8] Nevertheless, for irregular eutectics, the branching stiffness of the faceted phase gives rise to the formation of a truly three-dimensional (3-D) eutectic microstructure, where a governing theory for assessment of pattern selection criteria and microstructure characteristics is still missing.…”

Section: Introductionmentioning

confidence: 99%

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X-Ray Videomicroscopy Studies of Eutectic Al-Si Solidification in Al-Si-Cu

Mathiesen

Arnberg

et al. 2010

Metall Mater Trans A

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Al-Si eutectic growth has been studied in-situ for the first time using X-ray video microscopy during directional solidification (DS) in unmodified and Sr-modified Al-Si-Cu alloys. In the unmodified alloys, Si is found to grow predominantly with needle-like tip morphologies, leading a highly irregular progressing eutectic interface with subsequent nucleation and growth of Al from the Si surfaces. In the Sr-modified alloys, the eutectic reaction is strongly suppressed, occurring with low nucleation frequency at undercoolings in the range 10 K to 18 K. In order to transport Cu rejected at the eutectic front back into the melt, the modified eutectic colonies attain meso-scale interface perturbations that eventually evolve into equiaxed compositestructure cells. The eutectic front also attains short-range microscale interface perturbations consistent with the characteristics of a fibrous Si growth. Evidence was found in support of Si nucleation occurring on potent particles suspended in the melt. Yet, both with Sr-modified and unmodified alloys, Si precipitation alone was not sufficient to facilitate the eutectic reaction, which apparently required additional undercooling for Al to form at the Si-particle interfaces.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

X-Ray Videomicroscopy Studies of Eutectic Al-Si Solidification in Al-Si-Cu

Mathiesen

Arnberg

et al. 2010

Metall Mater Trans A

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“…According to the existing analytical models and experimental results [25][26][27] , the growth velocities of the two eutectic phases can be calculated as:…”

Section: Growth Kinetics and Capturing Rulementioning

confidence: 99%

Modeling studies on divorced eutectic formation of high pressure die cast magnesium alloy

Hua

Xiong

2018

China Foundry

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A s the lightest known structural metals, magnesium alloys have attracted much attention due to their superior properties such as low density, high specific strength, excellent castability, good machinability and recyclability [1,2] . Magnesium alloys have been widely used in automotive, aerospace and 3C (computer, communication and consumer electronics) industries to replace steel, cast iron and even aluminum alloy [3] . The high pressure die casting (HPDC) process is a netshape or near net-shape process with the advantages of high efficiency, considerable economic benefit and high precision of the product size. These remarkable advantages make the HPDC process particularly suitable for various complex productions with magnesium alloys, and generally, magnesium alloy parts are mainly formed by the HPDC process [4] .The performance of magnesium alloy die castings Abstract:The morphology and content of the divorced eutectic in the microstructure of high pressure die casting (HPDC) magnesium alloy have a great influence on the final performance of castings. Based on the previous work concerning simulation of the nucleation and dendritic growth of primary α-Mg during the solidification of magnesium alloy under HPDC process, an extension was made to the formerly established CA (Cellular Automaton) model with the purpose of modeling the nucleation and growth of Mg-Al eutectic. With a temperature field and solute field obtained during simulation of the primary α-Mg dendrites as the initial condition of the modified CA model, modeling of the Mg-Al eutectic with a divorced morphology was achieved. Moreover, the simulated results were in accordance with the experimental ones regarding the distribution and content of the divorced eutectic. Taking a "cover-plate" die casting with AM60 magnesium alloy as an example, the rapid solidification with a high cooling rate at the surface layer of the casting led to a fine and uniform grain size of primary α-Mg, while the divorced eutectic at the grain boundary revealed a more dispersed and granular morphology. Islands of divorced eutectic were observed at the central region of the casting, due to the existence of ESCs (Externally Solidified Crystals) which contributed to a coarse and non-uniform grain size of primary α-Mg. The volume percentage of the eutectic β-Mg 17 Al 12 phase is about 2%-6% in the die casting as a whole. The numerical model established in this study is of great significance to the study of the divorced eutectic in the microstructure of die cast magnesium alloy.

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“…Nevertheless, the wedge cannot be considered as a simple body. The wedge thin sections are heated up from the thicker sections, and this is not taken into account in Equation (16). Accordingly, Equation (17) is corrected to reflect this effect.…”

Section: Chillmentioning

confidence: 99%

“…Accordingly, Equation (17) is corrected to reflect this effect. Considering the experimental w and  values and plugging them into Equation (16), the modulus Mw can be estimated. Figure 4b shows the relationship between the modulus Mw and Mcr.…”

Section: Chillmentioning

confidence: 99%

Role of Alloying Additions in the Solidification Kinetics and Resultant Chilling Tendency and Chill of Cast Iron

Fraś

López

Kawalec

et al. 2015

Metals

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The present work describes the effect of the solidification processing and alloy chemistry on the chilling tendency index, CT, and the chill, w, of wedge-shaped castings made of cast iron. In this work, theoretical predictions were experimentally verified for the role of elements, such as C, Si, Mn, P and S, on the cast iron CT. In addition, inoculation and fading effects were considered in the experimental outcome. Accordingly, the graphite nucleation coefficients, Ns, b, the eutectic cell growth coefficient, μ, and the critical cooling rate, Qcr, for the development of eutectic cementite (chill) were all determined as a function of the cast iron chemistry and time after inoculation. In particular, it was found that increasing the Mn and S contents, as well as the time after inoculation lowers the critical cooling rate, thus increasing the chilling tendency of the cast iron. In contrast, C, Si and P increase the critical cooling rate, and as a result, they reduce the cast iron CT and chill.

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An analytical model of irregular eutectic growth and its application to Fe-C

Cited by 149 publications

References 9 publications

X-Ray Videomicroscopy Studies of Eutectic Al-Si Solidification in Al-Si-Cu

X-Ray Videomicroscopy Studies of Eutectic Al-Si Solidification in Al-Si-Cu

Modeling studies on divorced eutectic formation of high pressure die cast magnesium alloy

Role of Alloying Additions in the Solidification Kinetics and Resultant Chilling Tendency and Chill of Cast Iron

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