Effect of mixing rate on the morphology of primary Al phase in the controlled diffusion solidification (CDS) process

Khalaf, Abbas A.; Shankar, Sumanth

doi:10.1007/s10853-012-6711-9

Cited by 20 publications

(10 citation statements)

References 6 publications

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“…CDS technology employs a combination of solute and thermal fields to enable non-dendritic morphology of the casting [63]. The works of Saha et al [76], Symeonidis et al [77], and Khalaf et al [78][79][80] have resulted in a sound basis for successful CDS processing.…”

Section: Controlled Diffusion Solidification (Cds) Processmentioning

confidence: 99%

“…In this process, two precursor alloy melts with different thermal masses (temperature and mass) are mixed in such a way that the higher thermal mass melt is undercooled by the other . Numerous nucleation of solid nuclei within the undercooled melt, uniform distribution of the nuclei throughout the melt by the forced convection resulting from the mixing process and diffusion of alloying elements toward the solidifying front, leading to a negligible and diminishing chemical undercooling at the solid/liquid interface, prevent instability of the interface and thereby ensure the globular morphology .…”

Section: Controlled Diffusion Solidification (Cds) Processmentioning

confidence: 99%

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The role of indium in the activation of aluminum alloy galvanic anodes

Pourgharibshahi

Lambert

2015

Materials & Corrosion

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Despite six decades use of aluminum as a galvanic (sacrificial) anode, there remains a need for a better understanding of the underlying mechanisms for enhancing its efficient performance in cathodic protection systems. A few mechanisms have been proposed for the role of indium in the activation of Al‐Zn‐In anodes and there appears to be no general agreement on whether this element plays its depassivating role by modifying the bulk microstructure of the anode, chemical composition of its surrounding electrolyte or directly through doping the structure of the passive oxide film. These mechanisms have been critically reviewed to achieve a more comprehensive understanding of the role of indium in such applications. Moreover, the novel solidification processing called controlled diffusion solidification (CDS) has been introduced as an efficient way to surmount the poor castability of the anode alloy without any need for the addition of elements with detrimental effects on the electrochemical properties of the anode.

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Section: Controlled Diffusion Solidification (Cds) Processmentioning

confidence: 99%

Section: Controlled Diffusion Solidification (Cds) Processmentioning

confidence: 99%

The role of indium in the activation of aluminum alloy galvanic anodes

Pourgharibshahi

Lambert

2015

Materials & Corrosion

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“…Aluminum wrought alloys could not be easily cast by conventional casting processes because they are prone to make hot tearing during solidi cation, where the inter-dendritic liquid at the end of the solidi cation process cannot effectively feed the shrinkage cavities created during solidi cation of the primary, secondary, and ternary branches of the dendrites because of creating a large and complex dendritic network [3,4]. The CDS process is a casting process depending on mixing two precursor alloys that have different masses and temperatures to make copious nucleation that results in improving the mechanical properties by changing the microstructure from dendritic to small size nondendrites that leads to minimizing the hot tearing tendencies [5][6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

“…The mixing step, nucleation, and growth are the steps of the mechanism of the CDS process presented by Apelian [12], Symeonidis [13], and Khalaf [6]. The results achieved from the successful CDS process are small size globular morphologies forming from copious nucleation occurring during the CDS steps without needing to add a grain re ner [6,8,11,14,15]. Khalaf [16,17] used Al-Cu and Al-Zn binary alloys system to study the microstructure formed by the CDS process experimentally and by simulation, the results exhibited that globular, rosette, and dendrites coexist in the entire microstructure, even though all the morphologies were exposed to the same thermal environment during growth, further, anomalous morphologies form in the microstructure when using pure aluminum as a rst precursor alloy that has a higher liquidus temperature.…”

Section: Introductionmentioning

confidence: 99%

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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“…In addition, CDS is a simple and low-cost technology. In recent years, researchers have employed CDS to study the formation mechanism of the primary α-Al phase in Al-Cu wrought alloys [13] and Al-Si hypereutectic alloys [14,15] . However, very few reports are available on the effects of CDS on 7075 Al alloy.…”

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confidence: 99%

Microstructural evaluation and mechanical properties of 7075 aluminum alloy prepared by controlled diffusion solidification

Yang

Luo

et al. 2019

China Foundry

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In the present work, 7075 aluminum alloy (Al-Zn-Mg-Cu) was produced by both conventional casting (CC) and controlled diffusion solidification (CDS) methods. Each sample was subjected to different heat-treatment conditions: as-cast, T4, and T6; and their microstructural and mechanical properties were investigated by optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffractometry (XRD). It was found that CDS promoted the formation of non-dendritic primary α-Al phase and reduced shrinkage porosity, thus resulting in improved mechanical properties. In addition, the eutectic phase of the CDS samples mainly consisted of T(Al-Zn-Mg-Cu) phase, which manifested a well-developed lamellar eutectic structure. However, in the CC samples, the T(Al-Zn-Mg-Cu) phase was composed of rod-like eutectics. Moreover, the θ(Al 2 Cu) eutectic contents in the CC samples were greater than those in the CDS samples. Each element in the CC samples had an obvious change in the grain boundary, whereas the change in element content in the CDS samples was gradual. Therefore, the non-dendritic morphology of the primary phase and the presence of rod-like eutectics in the matrix of the CDS samples led to enhanced tensile strength and elongation under different heat treatment conditions.

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Effect of mixing rate on the morphology of primary Al phase in the controlled diffusion solidification (CDS) process

Cited by 20 publications

References 6 publications

The role of indium in the activation of aluminum alloy galvanic anodes

The role of indium in the activation of aluminum alloy galvanic anodes

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

Microstructural evaluation and mechanical properties of 7075 aluminum alloy prepared by controlled diffusion solidification

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