Change in Porosity of A356 by Holding Time and Its Effect on Mechanical Properties

Uludağ, Muhammet; Çetin, Remzi; Gemi, Lokman; Dışpınar, Derya

doi:10.1007/s11665-018-3534-0

Cited by 14 publications

(8 citation statements)

References 47 publications

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“…Double oxide defects are often too small to be detected by conventional X-ray investigations, and they are mainly investigated by destructive metallographic techniques, e.g. optical or scanning electron microscopy [10,12,14,22,26]. Recently, the spread of computer tomography and ultrafast synchrotron-based X-ray tomographic microscopy has allowed reconstructing the morphology of entrainment defects and investigating their evolution during solidification [20,21].…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…The decrease in the mechanical properties due to the presence of double oxide defects is well known [12][13][14], and it affects the components produced by gravity casting [15] and low-pressure casting [16,17]. An accurate preparation of the melt with degassing and filter systems is effective for preventing the entrainment of thick bifilms (thickness = 10 μm ÷ 1 mm) inside the casting [8,12,18]. In contrast, thinner bifilms, generated by the action of turbulence during the pouring and filling phases, are difficult to eliminate, due to their small size (thickness = 1 nm ÷ 1 μm) [5].…”

Section: Introductionmentioning

confidence: 99%

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Experimental and numerical investigations of oxide-related defects in Al alloy gravity die castings

Scampone

Pirovano²,

Mascetti³

et al. 2021

Int J Adv Manuf Technol

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This research aimed to study the formation and distribution of oxide-related defects in the gravity die casting process of an AlSi7Cu0.5Mg alloy by using experimental and numerical investigations. Metallographic and image analysis techniques were conducted to map the distribution of oxide inclusions inside the casting at the microscopic level. Numerical simulations were used to analyse the filling and solidification stages, and to foresee the turbulence of the melt and the formation of the oxide defects. The results show that most of the defects were correlated with the oxide layers or bubbles entrained inside the liquid metal. The accuracy of the numerical code in simulating the metal fluid-dynamic behaviour and the heat transfer was verified, and the results were in agreement with the experimental findings. The numerical distribution of defects was consistent with the experimental results, proving that the model successfully predicted the formation of oxide-related defects.

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Section: Theoretical Backgroundmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental and numerical investigations of oxide-related defects in Al alloy gravity die castings

Scampone

Pirovano²,

Mascetti³

et al. 2021

Int J Adv Manuf Technol

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“…[23,24,29] The effect of rotary degassing treatments on the bifilm content of liquid aluminum alloys is not straightforward, and the information available in the literature is often contradictory. Uludag˘et al, [30] as well as Uludagȃ nd Dispinar [31] reported that, based on lower Bifilm-Index values, degassing with Ar (for 15 and 20 minutes) effectively reduced bifilm quantity in A356 alloy melts. Contrary, several researchers reported higher bifilm quantity after rotary degassing treatments, which is commonly attributed to the surface turbulence and vortex formation around the impeller shaft, as well as the free melt surface sloshing near the vessel sidewalls, which phenomena can be avoided by using optimal treatment parameters.…”

Section: Introductionmentioning

confidence: 98%

The Effect of Rotary Degassing Treatments with Different Purging Gases on the Double Oxide- and Nitride Film Content of Liquid Aluminum Alloys

Gyarmati

Vincze

Fegyverneki

et al. 2022

Metall Mater Trans B

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Rotary degassing is one of the most frequently used melt treatment technologies used for processing liquid aluminum alloys. Despite this, the information available about the possible effects of this method on the double oxide- and nitride film (bifilm) content, especially when using different purging gases, is quite limited. For this reason, in this study, the effects of multiple rotary degassing treatments conducted with N2 and Ar purging gases on the bifilm quantity of a casting aluminum alloy were compared. The characterization of the melt quality was realized by the computed tomographic (CT) analysis of reduced pressure test (RPT) specimens, image analysis, and scanning electron microscopy (SEM) of the fracture surfaces of K-mold samples. Based on the results, by the application of Ar as a purging gas, relatively low bifilm content can be achieved. On the other hand, while the use of N2 leads to the formation of numerous small-sized nitride bifilms, which significantly increased the pore number density inside the RPT specimens. This can be associated with the nitride formation by the chemical reaction between the liquid aluminum alloy and the N2 purging gas bubbles during the degassing treatments. Graphical abstract

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“…For lightweight, tough, wear-resistant and low-cost FGM, designers are working on composite structures composed of dissimilar materials (Zhao et al, 2019;Wróbel, 2011). The notable merit of such dissimilar alloys is that a smooth change in properties can be achieved by combining different constituent alloys together, such as 304 stainless steel surface layer and a cast iron base by Ramadan (2015), and Ramadan et al (2017), two different Al-Si alloys by Scanlan et al (2005), a Babbitt-steel bimetal composite by Fathy et al (2018) and an Al/Mg alloy by Li et al (2019), Z. Jiang et al (2018) and W. Jiang et al (2016a).…”

Section: Introductionmentioning

confidence: 99%

Interfacial microstructures and properties of hyper-eutectic Al–21Si / hypo-eutectic Al–7.5Si bimetallic material fabricated by liquid–liquid casting route

Ramadan

Alghamdi

2020

Mech. Sci.

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Abstract. The bimetal casting process using the liquid–liquid technique was developed to produce a high-quality hyper-eutectic Al–21Si / hypo-eutectic Al–7.5Si alloy bimetal material. Microstructure and microhardness were investigated as a function of the time interval between pouring hypo-eutectic and hyper-eutectic alloys. A bimetal material was successfully fabricated using a liquid–liquid casting technique with a 10 s time interval in a permanent mould casting. A unique structure comprised of hyper-eutectic Al–21Si, hypo-eutectic Al–7.5Si and a eutectic interface of 70 µm thickness was obtained. This structure totally differs from that obtained using a higher time interval above 10 s that showed an imperfect interface bond due to the shrinkage cavity and formation of oxides. The hardness variation from the upper zone of 117.5 HV to the lower zone of 76 HV corresponded to the variation in Si and the content of other alloying elements. The proposed total solidification time control method is a promising approach for the successful fabrication of liquid–liquid bimetal material.

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Change in Porosity of A356 by Holding Time and Its Effect on Mechanical Properties

Cited by 14 publications

References 47 publications

Experimental and numerical investigations of oxide-related defects in Al alloy gravity die castings

Experimental and numerical investigations of oxide-related defects in Al alloy gravity die castings

The Effect of Rotary Degassing Treatments with Different Purging Gases on the Double Oxide- and Nitride Film Content of Liquid Aluminum Alloys

Interfacial microstructures and properties of hyper-eutectic Al–21Si / hypo-eutectic Al–7.5Si bimetallic material fabricated by liquid–liquid casting route

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