Digital twin for directional solidification of a single-crystal turbine blade

Zhang, Haijie; Liu, Xiaoshan; Ma, Dexin; Song, Min; Ludwig, Andreas; Kharicha, Abdellah; Wu, Menghuai

doi:10.1016/j.actamat.2022.118579

Cited by 13 publications

(11 citation statements)

References 41 publications

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“…At the peak of the inclined solidification front, the soluteenriched interdendritic liquid exhibited the highest gravitational potential energy to flow upwards, making it the preferred position for the formation of the plumes. This has been theorised in our previous work [10]. As shown in Figure 3(d), four plumes located as the casting corners further developed into stable freckles below the solidification front.…”

Section: Liquid Flow Patternsupporting

confidence: 69%

“…the filling process was ignored. The conservation of enthalpy was solved for the shell mould and casting, but only latent heat owing to solidification of the casting was treated with an equivalent specific heat method [10]. Flow and solidification were solved using the VA multiphase solidification model.…”

Section: Model Configuration and Calculation Methodsmentioning

confidence: 99%

“…The equiaxed grains, and the newly produced fragments, shall be remelted and destroyed if they are exposed to a hot liquid. Because the grain remelting was assumed to be governed by diffusion, equation (10) was valid to calculate the remelting speed vRe. In each calculation cell, the equiaxed grains were assumed to follow a lognormal size distribution, equation ( 8) [13].…”

Section: Table II Formulations For Capillarymentioning

confidence: 99%

“…The cooling history of the temperature distribution on the casting surface, as calculated by ProCAST, was used as the Dirichlet thermal boundary condition for the flow-solidification calculation using VA solidification model. The thermal coupling method has been introduced in [10]. As shown in Figure 1(b), a no-slip flow boundary condition was applied to the lateral wall of the sample, and a free-slip flow boundary condition was applied to the top surface.…”

Section: Table II Formulations For Capillarymentioning

confidence: 99%

“…Alternatively, numerical modelling has gradually made it possible to visualise the casting process and accurately predict the formation of freckles. According to state-of-the-art simulations [7][8][9][10], the freckles were indirectly predicted through the calculated segregation channels. The significant role of the fragments, which are the main source of the spurious grains, was ignored or roughly treated [11].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Numerical study on the formation of spurious grains and freckles during the directional solidification of superalloys

Zhang

Liu

et al. 2023

IOP Conf. Ser.: Mater. Sci. Eng.

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Freckles, a significant issue encountered during the directional solidification of superalloys, are recognised by a trail of equiaxed grains parallel to the direction of gravity accompanied by local eutectic enrichment. In the current study, a mixed-columnar-equiaxed multiphase volume-average solidification model was employed to study the formation of freckles in superalloy casting. Fragments produced via flow-driven and capillary-driven fragmentation mechanisms are considered as the source of spurious grains. The transport and the growth/remelting of the fragments are considered. According to the simulation results, some segregation channels develop at the corners of the casting. Flow-driven fragments are produced in/around the segregation channels, whereas capillary-driven fragments are produced at a certain depth of the mushy zone across the entire section of the casting. The fragmentation rate caused by the flow-driven mechanism is several orders of magnitude larger than that caused by the capillary-driven mechanism, i.e. the flow-driven fragmentation mechanism is dominant for the currently investigated sample. After the solidification process, four freckles formed at the casting corners on the shadowed side, whereas it was freckle-free on the bright side.

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Section: Liquid Flow Patternsupporting

confidence: 69%

Section: Model Configuration and Calculation Methodsmentioning

confidence: 99%

Section: Table II Formulations For Capillarymentioning

confidence: 99%

Section: Table II Formulations For Capillarymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Numerical study on the formation of spurious grains and freckles during the directional solidification of superalloys

Zhang

Liu

et al. 2023

IOP Conf. Ser.: Mater. Sci. Eng.

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Eliminating Equiaxed Grain Defects in a Ni‐Based Single‐Crystal Blade Platform by Flattening the Liquidus Isotherm

Szeliga

2023

Adv Eng Mater

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The article presents a mechanism for the formation of equiaxed grain defects and a new approach to eliminate them during the directional solidification of single‐crystal CMSX‐4 nickel‐based superalloy blades. The standard Bridgman method produces blade castings with clusters of equiaxed grains in platform areas above the root corners containing long freckle chains. The mechanism proposed considers the curvature of the liquidus isotherm and suggests that isolated dendrite fragments move upward from the freckle channel to the melt of the platform area. The floating surviving grains settle at the columnar dendrite tips, where they continue to grow into large equiaxed grains that block the development of the single‐crystal structure in the platform area located above the root corners. To eliminate these defects from the platform, a new approach is proposed, which involves introducing inner radiation baffles along the mold height to control the liquidus isotherm curvature in the blade. This stops the movement of small dendritic fragments from the root corner to the platform area, resulting in a significant reduction of freckles at the root and obtaining a typical single‐crystal structure free of equiaxed grains in the platform.

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Synthesis and characterisation of Fe38Al26Cu16Ni13Cr6 high entropy alloy processed through combined cable wire arc additive manufacturing (WAAM) process

Banerjee,

Mondal,

Haldar

et al. 2024

Int J Adv Manuf Technol

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Digital twin for directional solidification of a single-crystal turbine blade

Cited by 13 publications

References 41 publications

Numerical study on the formation of spurious grains and freckles during the directional solidification of superalloys

Numerical study on the formation of spurious grains and freckles during the directional solidification of superalloys

Eliminating Equiaxed Grain Defects in a Ni‐Based Single‐Crystal Blade Platform by Flattening the Liquidus Isotherm

Synthesis and characterisation of Fe38Al26Cu16Ni13Cr6 high entropy alloy processed through combined cable wire arc additive manufacturing (WAAM) process

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