Numerical and experimental investigation of microporosity formation in a ternary Al–Cu–Si alloy

Ferreira, Itamar; Lins, Jefferson Fabrício Cardoso; Moutinho, Daniel J.; Gómes, Laércio Gouvêa; Garcia, Amauri

doi:10.1016/j.jallcom.2010.04.244

Cited by 41 publications

(20 citation statements)

References 33 publications

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“…2,3) Because of the fundamental and practical importance, extensive efforts have been devoted to develop models for predicting the occurrence of porosity in castings. As reviewed by Lee et al 2) and Stefanescu,3) most models, [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] such as analytical solutions, criteria functions, Darcy's law coupled with the conservation and continuity equations, and gas diffusion-controlled pore growth models, focus on predicting the amount of porosity in a solidified casting, but without graphical morphology output.…”

Section: Introductionmentioning

confidence: 99%

Cellular Automaton Modeling of Microporosity Formation during Solidification of Aluminum Alloys

Zhu

et al. 2014

ISIJ Int.

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A two-dimensional (2D) cellular automaton (CA)-finite difference method (FDM) model is proposed to simulate the dendrite growth and microporosity formation during solidification of aluminum alloys. The model involves a three-phase system of liquid, gas, and solid. The growth of both dendrite and gas pore is simulated using a CA approach. The diffusion of solute and hydrogen is calculated using the FDM. The model is applied to simulate the formation and interactions of dendrites and micropores in an Al-7wt.%Si alloy. The effects of initial hydrogen concentration and cooling rate on microporosity formation are investigated. It is found that the porosity nuclei with larger size grow preferentially, while the growth of the small porosity nuclei is restrained. The competitive growth between porosities and dendrites is also observed. With the increase of initial hydrogen concentration, the incubation time of porosity nucleation and growth decreases, and the percentage of porosity increases, while porosity density does not increase apparently. With the decrease of cooling rate, porosity nucleates and starts to grow at higher temperatures, and the percentage of porosity increases, but the porosity density displays a decreasing trend. In addition, at a slower cooling rate, the competitive growth between porosities and dendrites becomes more evident, leading to a more non-uniform distribution of porosity size, and an increased maximum porosity size. The simulation results agree reasonably with the experimental data in the literature.

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Section: Introductionmentioning

confidence: 99%

Cellular Automaton Modeling of Microporosity Formation during Solidification of Aluminum Alloys

Zhu

et al. 2014

ISIJ Int.

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“…Nowadays these alloys are supplied in a wide range of chemical compositions [1][2][3][4][5][6][7][8][9][10][11][12]. We highlight the Al-Cu-Si ternary system because of particular outstanding properties such as high mechanical strength, low weight and very good fluidity [3][4][5][6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

“…This is known that the values of 1, 2 and 3 are strongly influenced by solidification thermal parameters such as growth rate (VL) and cooling rate (TR) [1,2,3,[7][8][9][10][11][12]. Several directional solidification studies have been reported in the literature to characterize and quantify these parameters as a function of solute concentration C0, VL and TR.…”

Section: Introductionmentioning

confidence: 99%

Influence of upward and horizontal growth direction on microstructure and microhardness of an unsteady-state directionally solidified Al-Cu-Si alloy

et al. 2016

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In order to analyze the effect of the growth direction on dendrite arm spacing (1) and microhardness (HV) during horizontal directional solidification (HDS), experiments were carried out with the Al-3wt.%Cu-5.5wt.%Si alloy and the results compared with others from the literature elaborated for upward directional solidification (UDS). For this purpose, a water-cooled directional solidification experimental device was developed, and the alloy investigated was solidified under unsteady-state heat flow conditions. Thermal parameters such as growth rate (VL) and cooling rate (TR) were determined experimentally and correlations among VL, TR, 1 and HV has been performed. It is observed that experimental power laws characterize 1 with a function of VL and TR given by: 1=constant(VL) -1.1 and 1=constant(TR) -0.55 . The horizontal solidification direction has not affected the power growth law of 1 found for the upward solidification. However, higher values of 1 have been observed when the solidification is developed in the horizontal direction. The interrelation of HV as function of VL, TR and 1 has been represented by power and Hall-Petch laws. A comparison with the Al-3wt.%Cu alloy from literature was also performed and the results show the Si element affecting significativaly the HV values.

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“…Studies on the transient solidifi cation of ternary alloys relating microstructural parameters and their correlations with mechanical properties have been developed in the literature (Atwood and Lee 2003, Costa et al 2015, Ferreira et al 2010, Sadrossadat and Johansson 2010, Swaminathan and Voller 1997, Voller 1998. The vast majority has been developed for vertical upward directional solidification (Easton et al 2010, Ferreira et al 2010, Rappaz and Boettinger 1999, Sadrossadat and Johansson 2010, Swaminathan and Voller 1997, Voller 1998.…”

Section: Introductionmentioning

confidence: 99%

“…The vast majority has been developed for vertical upward directional solidification (Easton et al 2010, Ferreira et al 2010, Rappaz and Boettinger 1999, Sadrossadat and Johansson 2010, Swaminathan and Voller 1997, Voller 1998. In the case of vertical upward directional solidifi cation, the infl uence of the convection is minimized when solute is rejected for the interdendritic regions, providing the formation of an interdendritic liquid denser than the global volume of liquid metal.…”

Section: Introductionmentioning

confidence: 99%

Interconnection between microstructure and microhardness of directionally solidified binary Al-6wt.%Cu and multicomponent Al-6wt.%Cu-8wt.%Si alloys

Vasconcelos

Kikuchi

Barros

et al. 2016

An. Acad. Bras. Ciênc.

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An experimental study has been carried out to evaluate the microstructural and microhardness evolution on the directionally solidifi ed binary Al-Cu and multicomponent Al-Cu-Si alloys and the infl uence of Si alloying. For this purpose specimens of Al-6wt.%Cu and Al-6wt.%Cu-8wt.%Si alloys were prepared and directionally solidifi ed under transient conditions of heat extraction. A water-cooled horizontal directional solidifi cation device was applied. A comprehensive characterization is performed including experimental dendrite tip growth rates (V L ) and cooling rates (T R ) by measuring Vickers microhardness (HV), optical microscopy and scanning electron microscopy with microanalysis performed by energy dispersive spectrometry (SEM-EDS). The results show, for both studied alloys, the increasing of T R and V L reduced the primary dendrite arm spacing (λ 1 ) increasing the microhardness. Furthermore, the incorporation of Si in Al-6wt.%Cu alloy to form the Al-6wt.%Cu-8wt.%Si alloy infl uenced signifi cantly the microstructure and consequently the microhardness but did not affect the primary dendritic growth law. An analysis on the formation of the columnar to equiaxed transition (CET) is also performed and the results show that the occurrence of CET is not sharp, i.e., the CET in both cases occurs in a zone rather than in a parallel plane to the chill wall, where both columnar and equiaxed grains are be able to exist.

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Numerical and experimental investigation of microporosity formation in a ternary Al–Cu–Si alloy

Cited by 41 publications

References 33 publications

Cellular Automaton Modeling of Microporosity Formation during Solidification of Aluminum Alloys

Cellular Automaton Modeling of Microporosity Formation during Solidification of Aluminum Alloys

Influence of upward and horizontal growth direction on microstructure and microhardness of an unsteady-state directionally solidified Al-Cu-Si alloy

Interconnection between microstructure and microhardness of directionally solidified binary Al-6wt.%Cu and multicomponent Al-6wt.%Cu-8wt.%Si alloys

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