Studying of Non-Dendritic Microstructure Forming in Controlled Diffusion Solidification

Khalaf, Abbas A.

doi:10.1007/s40962-021-00590-y

Cited by 7 publications

(7 citation statements)

References 16 publications

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“…Table 1 presents the list of the experiments carried out along with the independent parameters and constants. The experimental procedure, the crucible and funnel dimensions, and the schematic diagram of the setting up of the funnel and the crucible for the CDS process have been discussed in detail previously [11,16,17]. Fig.…”

Section: Methodsmentioning

confidence: 99%

“…According to the phase diagram, the maximum difference in the initial temperature between the pure aluminum and the eutectic alloys was 110 and 83°C employed by Al-Cu and Al-Si systems, respectively. Where, a higher difference between the temperatures of the two precursor alloys that are mixed at a temperature near to their respective liquidus temperature leads to a higher undercooling of the rst precursor alloy happening during the mixing step resulting in a drastic increase in the nucleation rate [16,17]. In addition, according to the level rule, the mass ratios (mr=m1/m2) required to make the resultant alloys are 6.3 and 1.82 for Al-Cu and Al-Si, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…One can suggest that the lower difference in the initial temperature for the Al-Si system decreases the undercooling of Alloy1during the mixing step, this leads to a decrease in the nucleation rate. In addition, the lower mass ratio increases the amount of the dendritic morphologies forming among the globular and rosette morphologies creating in the microstructure of the hypoeutectic alloys formed by the CDS process [12,[15][16][17]. According to that, the microstructure of the Al-Si hypoeutectic alloys is expected to have more dendritic morphologies forming in the entire product made by the CDS process especially for the alloys that have a silicon content of more than 4.5 wt%Si when mixing pure aluminum into a hypoeutectic alloy.…”

Section: Methodsmentioning

confidence: 99%

“…Khalaf et al [6,[10][11][12][13][14][15][16]used the CDS process to mix pure aluminum with Al-Cu binary alloys that have different solute contents, the results show that the microstructure forms from globular morphologies, globular mixed with rosette morphologies, and rosette mixed with dendritic morphologies, where the change in the microstructure strongly depends on the mass ratio and the undercooling of the rst precursor alloy. The undercooling strongly depends on the difference between the initial temperatures of the two precursor alloys prior to the mixing step [12,17].…”

Section: Introductionmentioning

confidence: 99%

“…Yang et al [23] used the CDS process to make 7050 alloy by mixing pure aluminum into Al-Zn11.2-Mg5-Cu3 (wt%) alloy, the non-dendritic microstructure forms the resultant alloy. Khalaf [17] used Al-Zn binary alloys to study the microstructure of the CDS process, where pure aluminum was mixed into Al-Zn binary alloys at different mass ratios to make Al-4.5 wt%Zn as a resultant alloy. The nal results were compared with Al-Cu alloys.…”

Section: Introductionmentioning

confidence: 99%

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Microstructure evolution of Al-Si hypoeutectic alloys prepared by controlled diffusion solidification

Khalaf

2022

Int J Adv Manuf Technol

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The possibility of changing the dendritic microstructure associated with the conventional casting processes of hypoeutectic Al-Si alloys to non-dendritic microstructure by using the controlled diffusion solidi cation process (CDS) has been investigated. The successful CDS process depends on mixing two precursor alloys heated at a superheat condition near their respective liquidus temperature. Experimental work and simulation work using Ansys software was carried out in the present study by employing Al-Si and Al-Cu systems. This study investigates the effect of the content of the two precursor alloys, the mass ratio changing from 2.6 to 8.3, and the superheat of the rst precursor alloy on changing the microstructure. The experimental results show that the pure aluminum used as the rst precursor alloy needs more undercooling and agitation during the mixing to form the non-dendritic microstructure compared with hypoeutectic Al-Si alloys. Further, mixing pure aluminum with hypereutectic alloy can change the microstructure of hypoeutectic alloys leading to extending the possibility to choose the second precursor alloy. The results also show that a higher mass ratio is preferred when mixing pure aluminum with hypoeutectic alloy. Furthermore, the microstructure of the alloy Al-6.45Si-4Cu-0.5Mg-0.66Fe-0.66 wt%Zn was successfully changed via the CDS process by mixing Al-7.75Si-0.79Fe-0.78Zn-0.6 wt%Mg at 2°C superheat into Al-24 wt%Cu at around 5°C superheat. The simulation results show that lower air bubbles and better distribution of the two precursor alloys happen during the mixing step when using the Al-Cu system.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Microstructure evolution of Al-Si hypoeutectic alloys prepared by controlled diffusion solidification

Khalaf

2022

Int J Adv Manuf Technol

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Temperature, density, and velocity distribution in the mixture prepared by controlled diffusion solidification process

Khalaf

2022

Int J Adv Manuf Technol

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Controlled diffusion solidi cation (CDS) is a new casting process that depends on mixing two precursor alloys. The two precursor alloys have precisely controlled temperature and content to make a required resultant alloy. The CDS process can change the microstructure to non-dendritic happening from copious nucleation, resulting in minimizing the tendency toward the hot tearing. Contrary to the conventional casting in which the dendritic microstructure forms the entire microstructure of the product. In the present study, Pure aluminum and Al-33wt%Cu have been used to make Al-4.7wt%Cu by using the CDS technique, where the pure aluminum was mixed into Al-33wt%Cu through funnels that have 9 and 6mm diameter. The events such as the nucleation and heat transfer to the environment have been studied with aid of the temperature, density, and velocity distribution taking place during the mixing step of the CDS process. The results show that the thermal curves give better indications to predict the periods of nucleation and the heat transferring to the environment. Further, the copious nucleation that occurs in the CDS process can be improved by controlling the agitation during the mixing step by decreasing the velocity of the mixture near the crucible wall and increasing the velocity in the middle of the mixture. Ansys software was employed to simulate the temperature, density, and velocity distribution in the mixture during the mixing step. The experimental results were supported by simulation results and an optical microscopy test.

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Mixing process and nucleation of an Al-Si alloy during controlled diffusion solidification with simultaneous mixing and effect of mixing rate

et al. 2022

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Studying of Non-Dendritic Microstructure Forming in Controlled Diffusion Solidification

Cited by 7 publications

References 16 publications

Microstructure evolution of Al-Si hypoeutectic alloys prepared by controlled diffusion solidification

Microstructure evolution of Al-Si hypoeutectic alloys prepared by controlled diffusion solidification

Temperature, density, and velocity distribution in the mixture prepared by controlled diffusion solidification process

Mixing process and nucleation of an Al-Si alloy during controlled diffusion solidification with simultaneous mixing and effect of mixing rate

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