The Experts below are selected from a list of 2436 Experts worldwide ranked by ideXlab platform
B Zhang - One of the best experts on this subject based on the ideXlab platform.
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effect of low frequency magnetic field on microstructures and Macrosegregation of horizontal direct chill casting 7075 aluminum alloy
Journal of Materials Processing Technology, 2007Co-Authors: Zhihao Zhao, J Dong, Jianzhong Cui, B ZhangAbstract:Abstract The horizontal direct chill (HDC) casting process is a well-established production route for an aluminum alloy ingot; however, the ingot may suffer from inhomogeneous microstructures and serious Macrosegregation due to the unbalanced cooling condition and gravitational effect. In order to control the defect, a low frequency electromagnetic field has been applied in the HDC casting process and its influences on cast surface, microstructures and Macrosegregation have been studied. The results show that the low frequency electromagnetic field can effectively improve surface quality, reduce inhomogeneous microstructures and Macrosegregation in HDC product; and two main parameters of the electromagnetic field—density and frequency, significantly influence the microstructures and solution distribution along the diameter of the ingot. In the range of ampere-turns and frequency employed in the experiments, the optimum ampere-turns and frequency are found to be 10,000 At, 30 Hz.
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effects of low frequency electromagnetic field on microstructures and Macrosegregation of continuous casting 7075 aluminum alloy
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2003Co-Authors: B Zhang, Jianzhong Cui, Guimin LuAbstract:The influences of low-frequency electromagnetic field on microstructures and Macrosegregation in continuous casting process were investigated experimentally. Ingot of 7075 aluminum alloy with a diameter of 200 mm was produced and as-cast structures were examined. In the presence of an electromagnetic field, a substantial reduction of grain size and the Macrosegregation of alloying elements was achieved. Further, a pronounced evolution of microstructures and segregation with the frequency of electromagnetic field is presented. The results show that frequency plays a significant role in grain refinement and Macrosegregation inhibition. A fine equiaxed as-cast structure is obtained when frequency reaches 15 Hz, while a proper frequency (30 Hz in this study) can inhibit the Macrosegregation to the best effect.
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effect of low frequency magnetic field on Macrosegregation of continuous casting aluminum alloys
Materials Letters, 2003Co-Authors: B Zhang, Guimin LuAbstract:The influence of electromagnetic field on Macrosegregation of continuous casting aluminum alloy is studied in this paper. 7075 aluminum alloy ingot of 200-mm diameter is produced by electromagnetic casting process; intensity of the coil current is varied from 100 to 600 A, and frequency is from 10 to 100 Hz. Variation of solute content along the radius of ingot is examined by means of chemical analysis. The results show that electromagnetic casting process can effectively reduce Macrosegregation, and electromagnetic frequency has a great influence on solute distribution along the radius of ingot. When frequency is 30 Hz, Macrosegregation is eliminated completely.
Guimin Lu - One of the best experts on this subject based on the ideXlab platform.
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effects of low frequency electromagnetic field on microstructures and Macrosegregation of continuous casting 7075 aluminum alloy
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2003Co-Authors: B Zhang, Jianzhong Cui, Guimin LuAbstract:The influences of low-frequency electromagnetic field on microstructures and Macrosegregation in continuous casting process were investigated experimentally. Ingot of 7075 aluminum alloy with a diameter of 200 mm was produced and as-cast structures were examined. In the presence of an electromagnetic field, a substantial reduction of grain size and the Macrosegregation of alloying elements was achieved. Further, a pronounced evolution of microstructures and segregation with the frequency of electromagnetic field is presented. The results show that frequency plays a significant role in grain refinement and Macrosegregation inhibition. A fine equiaxed as-cast structure is obtained when frequency reaches 15 Hz, while a proper frequency (30 Hz in this study) can inhibit the Macrosegregation to the best effect.
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effect of low frequency magnetic field on Macrosegregation of continuous casting aluminum alloys
Materials Letters, 2003Co-Authors: B Zhang, Guimin LuAbstract:The influence of electromagnetic field on Macrosegregation of continuous casting aluminum alloy is studied in this paper. 7075 aluminum alloy ingot of 200-mm diameter is produced by electromagnetic casting process; intensity of the coil current is varied from 100 to 600 A, and frequency is from 10 to 100 Hz. Variation of solute content along the radius of ingot is examined by means of chemical analysis. The results show that electromagnetic casting process can effectively reduce Macrosegregation, and electromagnetic frequency has a great influence on solute distribution along the radius of ingot. When frequency is 30 Hz, Macrosegregation is eliminated completely.
Hervé Combeau - One of the best experts on this subject based on the ideXlab platform.
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effect of the coriolis force on the Macrosegregation of aluminum in the centrifugal casting of ti al alloys
IOP Conference Series: Materials Science and Engineering, 2019Co-Authors: Cisternas M Fernandez, Miha Založnik, Hervé Combeau, Julien Zollinger, Chunmei Huang, U HechtAbstract:Within the framework of the ESA GRADECET project, experiments of directional solidification of cylindrical Ti-Al samples were conducted in hypergravity. The experiments were performed in a centrifuge with the apparent gravity (sum of centrifugal and terrestrial gravity) aligned along the cylinder centerline. 3D numerical simulations of aluminum Macrosegregation in these samples are presented. A volume-averaging solidification model is used that accounts for centrifugal and Coriolis accelerations in a non-inertial rotating reference system. We compare the melt flow pattern and the Macrosegregation formation under terrestrial gravity and under centrifugation. The results show that the Coriolis acceleration, although very weak, breaks the symmetry of the thermosolutal convection, having an important impact on the final Macrosegregation pattern. The Macrosegregation is entirely modified in comparison with a sample solidified under terrestrial gravity conditions. Besides the aluminum segregation intensity increases with the centrifugation level.
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A Simplified Three-Phase Model of Equiaxed Solidification for the Prediction of Microstructure and Macrosegregation in Castings
Metallurgical and Materials Transactions A, 2018Co-Authors: Knut Omdal Tveito, Hervé Combeau, Akash Pakanati, Mohammed M’hamdi, Miha ZaložnikAbstract:Macrosegregation is a result of the interplay of various transport mechanisms, including natural convection, solidification shrinkage, and grain motion. Experimental observations also indicate the impact of grain morphology, ranging from dendritic to globular, on Macrosegregation formation. To avoid the complexity arising due to modeling of an equiaxed dendritic grain, we present the development of a simplified three-phase, multiscale equiaxed dendritic solidification model based on the volume-averaging method, which accounts for the above-mentioned transport phenomena. The validity of the model is assessed by comparing it with the full three-phase model without simplifications. It is then applied to qualitatively analyze the impact of grain morphology on Macrosegregation formation in an industrial scale direct chill cast aluminum alloy ingot.
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Investigation of Macrosegregation Formation in Aluminium DC Casting for Different Alloy Systems
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 2018Co-Authors: Akash Pakanati, Hervé Combeau, Mohammed M’hamdi, Miha ZaložnikAbstract:Direct chill (DC) casting of aluminum involves alloys employing different solute elements. In this article, a qualitative analysis and comparison of Macrosegregation formation is presented for three different alloy systems: Al-Mg, Al-Zn and Al-Cu. For this purpose, a multiphase, multiscale solidification model based on a volume-averaging method accounting for shrinkage-induced flow, thermal-solutal convection and grain motion is used and applied to an industrial-scale DC-cast ingot. The primary difference between these alloys is the thermal-solutal convection with Al-Mg having a competing thermal and solutal convection, whereas the other two systems have a cooperating thermal and solutal convection. In the study, the combined effect of the Macrosegregation mechanisms is analyzed for each alloy to assess the role of the alloy system on the final Macrosegregation.
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influence of transport mechanisms on Macrosegregation formation in direct chill cast industrial scale aluminum alloy ingots
Advanced Engineering Materials, 2011Co-Authors: Miha Založnik, Hervé Combeau, Arvind Kumar, Marie Bedel, Philippe Jarry, Emmanuel WazAbstract:The phenomena responsible for the formation of Macrosegregations and grain structures during solidification are closely related. We present a model study of Macrosegregation formation in an industrial sized (350 mm thick) direct chill (DC) cast aluminum alloy slab. The modeling of these phenomena in DC casting is a challenging problem mainly due to the size of the products, the variety of the phenomena to be accounted for, and the nonlinearities involved. We used a volume-averaged two-phase multiscale model that describes nucleation on grain refiner particles and grain growth, fully coupled with macroscopic transport: fluid flow driven by natural convection and shrinkage, transport of free-floating equiaxed grains, heat transfer, and solute transport. The individual and combined roles of shrinkage, natural convection, and grain motion on the sump profile and Macrosegregation formation are analyzed. The formation and evolution of grains are discussed. We show that it is important to account for all the named transport mechanisms to be able to explain the Macrosegregation pattern observed experimentally in DC cast ingots.
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microsegregation Macrosegregation and related phase transformations in tial alloys
Intermetallics, 2011Co-Authors: D Daloz, Hervé Combeau, U Hecht, Julien Zollinger, Alain Hazotte, Miha ZaložnikAbstract:Abstract In the first part of the paper the influences of microsegregation on the microstructure establishment in Ti–Al based alloys are described. Examples are taken concerning the primary solidification phase, the grain refinement through boron addition, the occurrence of B2 phase in as-cast parts and the link between microsegregation and creep properties. In the second part, a numerical model of Macrosegregation devoted to centrifugal casting of TiAl alloys is presented and the influences of the parameters of the model are discussed.
J Dong - One of the best experts on this subject based on the ideXlab platform.
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effect of process parameters on structure and Macrosegregation upon direct chill casting of mg nd zn zr alloy
Materials Science and Technology, 2011Co-Authors: Xingwei Zheng, J Dong, N Zhou, S S Yao, W J DingAbstract:Direct chill (DC) semicontinuous casting process has been successfully used to produce sound Mg–3·0Nd–0·4Zn–0·4Zr (NZ30K) billets. The influence of process parameters such as casting speed, casting temperature on the microstructure and Macrosegregation was studied. The results show that the casting speed affects the Macrosegregation greatly while it has a slight influence on the grain size of the billet; the casting temperature has a slight influence on Macrosegregation of the billet while the grain size of the billet increases as the casting temperature increases. The optimal process parameters have been experimentally determined as follows: casting temperature 700°C and casting speed 90 mm min−1. The ultimate tensile strength, yield strength and elongation of billets cast at the optimal casting parameters are 196 MPa, 125 MPa and 16·5% respectively.
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effect of low frequency magnetic field on microstructures and Macrosegregation of horizontal direct chill casting 7075 aluminum alloy
Journal of Materials Processing Technology, 2007Co-Authors: Zhihao Zhao, J Dong, Jianzhong Cui, B ZhangAbstract:Abstract The horizontal direct chill (HDC) casting process is a well-established production route for an aluminum alloy ingot; however, the ingot may suffer from inhomogeneous microstructures and serious Macrosegregation due to the unbalanced cooling condition and gravitational effect. In order to control the defect, a low frequency electromagnetic field has been applied in the HDC casting process and its influences on cast surface, microstructures and Macrosegregation have been studied. The results show that the low frequency electromagnetic field can effectively improve surface quality, reduce inhomogeneous microstructures and Macrosegregation in HDC product; and two main parameters of the electromagnetic field—density and frequency, significantly influence the microstructures and solution distribution along the diameter of the ingot. In the range of ampere-turns and frequency employed in the experiments, the optimum ampere-turns and frequency are found to be 10,000 At, 30 Hz.
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effect of low frequency electromagnetic field on microstructures and Macrosegregation of φ270 mm dc ingots of an al zn mg cu zr alloy
Materials Letters, 2005Co-Authors: Jianzhong Cui, J Dong, Xiaoqin Zeng, Wenjiang DingAbstract:Compared with traditional direct chilling casting (DC) ingot, the edge and center microstructures of Φ270 mm low-frequency electromagnetic casting (LFEC) ingot are fine and uniform; and the Macrosegregation is also greatly reduced. When the electromagnetic intensity is kept as 9000 At, with decreasing the frequency, the center microstructures are much finer and the Macrosegregation is much lower. In the range of frequency employed in the experiments, the optimum frequency is found to be 15 Hz.
Jianzhong Cui - One of the best experts on this subject based on the ideXlab platform.
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effect of low frequency magnetic field on microstructures and Macrosegregation of horizontal direct chill casting 7075 aluminum alloy
Journal of Materials Processing Technology, 2007Co-Authors: Zhihao Zhao, J Dong, Jianzhong Cui, B ZhangAbstract:Abstract The horizontal direct chill (HDC) casting process is a well-established production route for an aluminum alloy ingot; however, the ingot may suffer from inhomogeneous microstructures and serious Macrosegregation due to the unbalanced cooling condition and gravitational effect. In order to control the defect, a low frequency electromagnetic field has been applied in the HDC casting process and its influences on cast surface, microstructures and Macrosegregation have been studied. The results show that the low frequency electromagnetic field can effectively improve surface quality, reduce inhomogeneous microstructures and Macrosegregation in HDC product; and two main parameters of the electromagnetic field—density and frequency, significantly influence the microstructures and solution distribution along the diameter of the ingot. In the range of ampere-turns and frequency employed in the experiments, the optimum ampere-turns and frequency are found to be 10,000 At, 30 Hz.
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effect of low frequency electromagnetic field on microstructures and Macrosegregation of φ270 mm dc ingots of an al zn mg cu zr alloy
Materials Letters, 2005Co-Authors: Jianzhong Cui, J Dong, Xiaoqin Zeng, Wenjiang DingAbstract:Compared with traditional direct chilling casting (DC) ingot, the edge and center microstructures of Φ270 mm low-frequency electromagnetic casting (LFEC) ingot are fine and uniform; and the Macrosegregation is also greatly reduced. When the electromagnetic intensity is kept as 9000 At, with decreasing the frequency, the center microstructures are much finer and the Macrosegregation is much lower. In the range of frequency employed in the experiments, the optimum frequency is found to be 15 Hz.
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effects of low frequency electromagnetic field on microstructures and Macrosegregation of continuous casting 7075 aluminum alloy
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2003Co-Authors: B Zhang, Jianzhong Cui, Guimin LuAbstract:The influences of low-frequency electromagnetic field on microstructures and Macrosegregation in continuous casting process were investigated experimentally. Ingot of 7075 aluminum alloy with a diameter of 200 mm was produced and as-cast structures were examined. In the presence of an electromagnetic field, a substantial reduction of grain size and the Macrosegregation of alloying elements was achieved. Further, a pronounced evolution of microstructures and segregation with the frequency of electromagnetic field is presented. The results show that frequency plays a significant role in grain refinement and Macrosegregation inhibition. A fine equiaxed as-cast structure is obtained when frequency reaches 15 Hz, while a proper frequency (30 Hz in this study) can inhibit the Macrosegregation to the best effect.
