Effect of Ceramic Cores on the Freckle Formation During Casting Ni-Based Single Crystal Superalloys

Wang, F.; X., D.; Bührig–Polaczek, Andreas

doi:10.1007/s11661-018-5049-6

Cited by 13 publications

(11 citation statements)

References 25 publications

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“…Single crystal: any study that talks in depth about the single crystal process and the procedure for producing a single crystal structure or its effects and benefits on the final casting [4,17,19,24,26,27,33,38,41,48,49,56,57,62,[72][73][74] 9…”

Section: Research Areamentioning

confidence: 99%

“…Advances in Materials Science and Engineering [13,25,39,59,69] Microstructure: any study that talked in depth about the microstructure of the alloys used and its effect on alloy properties and quality [7, 9-12, 15, 16, 18, 20, 22, 23, 29, 31, 32, 34, 35, 39, 46, 52, 54, 55, 57, 59, 67, 68, 72, 74, 76, 77, 79-84] Fracture mode: any study that talks about the fracture mechanisms, modes, and crack propagation taking place in superalloys [3, 10, 11, 13, 19, 20, 22, 30, 31, 37, 41, 43, 47, 53-55, 58, 59, 67, 77, 85] Ductility [37] Grain or dendrite size: any study that talks in depth about the grain or dendrite size, PDAS value, SDAS value, carbide size, or other precipitate sizes [11, 12, 16, 22, 34-36, 59, 66, 79, 80, 82, 86] Grain refinement: any study that talks about grain refinement, the process of refinement, and how and why the refinement takes place [16,17,34,48,49,80,87,88] Additive manufacturing: any study in which AM process was used [10] Hot isostatic pressing: any study in which the HIP process was used [3,14,58,67,89] Vacuum condition: any study that talked in depth about the effects of using vacuum conditions during casting procedure [26] Effect of alloying elements: any study that talks about the effects of different alloying elements and how varying their contents can affect the final product [7,40,42,55,59,73,76,77,82,83,90] Advances in Materials Science and Engineering…”

Section: Research Areamentioning

confidence: 99%

“…Withdrawal rates: any study that has performed extensive examination into the withdrawal rate used during the casting procedure and its impact on the casting properties [8,18,26,32,35,49,50] 42…”

Section: Research Areamentioning

confidence: 99%

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Recent Advancements in the Field of Ni‐Based Superalloys

Selvaraj

Sundaramali

Dev

et al. 2021

Advances in Materials Science and Engineering

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In this review article, research papers related to recent developments in Ni-superalloy technologies have been reviewed in order to provide an insight into recent achievements and the potential for further study, research, and development in this field. In this paper, studies on various aspects of Ni-based superalloys are reviewed, such as production methods, which include widely used casting methods, as well as unconventional alternative procedures, novel techniques, or simulation and prediction of certain alloy casting properties. Reviewing was done by categorising the papers into 4 major categories: manufacturing of Ni-based superalloys, effects of alloying elements, physical and mechanical properties of Ni-based superalloys, and defects in Ni-based superalloys. The process used to make Ni-superalloy parts can have a huge impact on the production process efficiency, the final product’s quality and properties, and the defects formed in it. Investment casting is one of the most common methods for making Ni-superalloy parts. Manufacturing covers studies on various casting methods used to make Ni-based superalloy components, novel techniques and methods developed to improve casting procedures to produce better products, and alternative manufacturing methods like AM and HIP processing. Similar to production process, the role of alloying elements is also very important. Even minor changes in their compositions can cause significant changes in the final product. Simultaneously, these alloying elements appear to be more efficient in the development of new methods to control product quality, suppress defect formation, and improve material properties such as the creep and fatigue. As a result, the effects of various alloying elements used in castings of Ni-based superalloys are thoroughly examined. A material’s properties are its most important components. They assist the industrialist in selecting or developing a material based on the needs of the application/use. With this in mind, many researchers have conducted extensive research on physical and mechanical properties, as well as how to improve them. Fatigue life, stress rupture, creep properties, impact ductility, strain response, stress relaxation behaviour, and so on are some of the most important physical and mechanical properties of Ni-superalloys. This article thoroughly reviews various studies on these properties, how and by what factors they are affected, and how they can be improved. Another important factor to consider when making Ni-superalloy castings is defect formation, which can affect the properties of the final product. Freckle defects, hot tears, porosities, and slivers are some of the major defects that occur in Ni-superalloys during the casting process. This article also reviews in detail about these defects, how they form, and how they affect the final product. These defects were found to have a significant influence on a variety of properties, such as creep, fatigue behaviour, and fracture mechanism. Topics and areas such as reinforcement of Ni-superalloys with the help of CNCs and 3D printing of Ni-superalloys that can provide scope for potential future research are highlighted based on the above-reviewed papers.

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Section: Research Areamentioning

confidence: 99%

Section: Research Areamentioning

confidence: 99%

See 1 more Smart Citation

Recent Advancements in the Field of Ni‐Based Superalloys

Selvaraj

Sundaramali

Dev

et al. 2021

Advances in Materials Science and Engineering

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“…Based on our recent work, [37,38] freckles occur not only on the external surfaces, but also inside the castings where a core was inserted. This is also attributed to the above-stated surface effect or wall effect, because both the shell and core wall can provide very high permeability for freckling convection in the mushy zone.…”

Section: DX Ma Zh Dong F Wang and Hb Dongmentioning

confidence: 99%

A Phenomenological Analysis of Freckling in Directional Solidification of Ni-Base Superalloy: The Role of Edge and Curvature in Casting Components

Dong

Wang

et al. 2019

Metall Mater Trans A

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The geometrical factor in freckle formation has rarely been taken into account. In this work, freckle formation in superalloy components is examined. It is found that freckle formation is subject to the effects of the edge and curvature. In polygonal casting sections, freckles are formed preferably on the convex edges. In the components with a curved contour, freckles are exclusively formed on the outward-curving surface having positive curvature.

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“…[5,6] It is generally believed that thermosolutal convection driven by density inversion in the mushy zone is the reason for freckle formation. [3,[7][8][9] Such density variation originating from dendritic segregation causes unstable fluid flow of the low density interdendritic liquid in the mushy zone, which results in fragmentation of dendrite arms. These dendrite fragments will finally develop into freckle defects.…”

Section: Introductionmentioning

confidence: 99%

Influence of Geometric Structure and Feeding Behavior of Casting on Freckle Formation during Directional Solidification of a Ni‐Based Single‐Crystal Superalloy

Han

Jiang

Xiao

et al. 2021

Crystal Research and Technology

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Determining the effect of casting geometric structure on freckle formation is important in designing the directional solidification parameter of single-crystal superalloy castings. In this research, single-crystal castings of a third-generation nickel (Ni)-based superalloy with different thicknesses and structures are prepared by conventional Bridgman high-rate-solidification technique at withdrawal rates of 1, 3, and 6 mm min -1 . The experimental results show that the freckles in castings with expansion structures are severer than those with contraction structures at a withdrawal rate of 1 mm min -1 , and vice versa at withdrawal rates of 3 and 6 mm min -1 . It is found that the larger casting thickness tends to promote the freckle formation at the same withdrawal rate. Furthermore, a lower tendency is displayed at the withdrawal rate of 3 mm min -1 in freckle formation, whereas an increased tendency is displayed at the withdrawal rate of 6 mm min -1 . The different withdrawal rates, thicknesses, and structures of casting cause differences in cooling rate, shrinkage flow, and mushy zone morphology, which are believed to be responsible for the tendency of freckle formation.

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Effect of Ceramic Cores on the Freckle Formation During Casting Ni-Based Single Crystal Superalloys

Cited by 13 publications

References 25 publications

Recent Advancements in the Field of Ni‐Based Superalloys

Recent Advancements in the Field of Ni‐Based Superalloys

A Phenomenological Analysis of Freckling in Directional Solidification of Ni-Base Superalloy: The Role of Edge and Curvature in Casting Components

Influence of Geometric Structure and Feeding Behavior of Casting on Freckle Formation during Directional Solidification of a Ni‐Based Single‐Crystal Superalloy

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